UPGRADING REPAIRING PCs

UPGRADING 

AND 

REPAIRING PCs 

TECHNICIAN’S PORTABLE 

REFERENCE 

SECOND EDITION 

Scott Mueller and Mark Edward Soper

Upgrading and Repairing PCs 

Technician’s Portable Reference, 

Second Edition 

Copyright© 2001 by Que 

All rights reserved. No part of this book shall be reproduced, stored 

in a retrieval system, or transmitted by any means, electronic, 

mechanical, photocopying, recording, or otherwise, without written 

permission from the publisher. No patent liability is assumed 

with respect to the use of the information contained herein. 

Although every precaution has been taken in the preparation of 

this book, the publisher and authors assume no responsibility for 

errors or omissions. Neither is any liability assumed for damages 

resulting from the use of the information contained herein. 

International Standard Book Number: 0-7897-2454-5 

Library of Congress Catalog Card Number: 00-104012 

Printed in the United States of America 

First Printing: October 2000 

02 01 00 4 3 2 1 

Trademarks 

All terms mentioned in this book that are known to be trademarks 

or service marks have been appropriately capitalized. Que cannot 

attest to the accuracy of this information. Use of a term in this 

book should not be regarded as affecting the validity of any trademark 

or service mark. 

Warning and Disclaimer 

Every effort has been made to make this book as complete and 

accurate as possible, but no warranty or fitness is implied. The 

information provided is on an as is basis. The authors and the publisher 

shall have neither liability nor responsibility to any person or 

entity with respect to any loss or damages arising from the information 

contained in this book.

Associate Publisher 

Greg Wiegand 

Senior Acquisitions Editor 

Jill Byus Schorr 

Senior Development Editor 

Rick Kughen 

Managing Editor 

Thomas F. Hayes 

Project Editor 

Karen S. Shields 

Copy Editor 

Megan Wade 

Technical Editor 

Mark Reddin 

Proofreader 

Jeanne Clark 

Indexer 

Mary SeRine 

Interior Design 

Kevin Spear 

Cover Design 

Karen Ruggles 

Layout Technicians 

Heather Hiatt Miller 

Stacey Richwine-DeRome 

iii

Contents at a Glance 

1 General Technical Reference 1 

2 System Components and Configuration 19 

3 BIOS Configurations and Upgrades 69 

4 SCSI and IDE Hard Drives and Optical Drives 93 

5 Floppy, Removable, Tape, and Flash Memory Storage 143 

6 Serial Ports and Modems 165 

7 Parallel Ports, Printers, Scanners, and Drives 189 

8 USB and IEEE-1394 Ports and Devices 205 

9 Keyboards, Mice, and Input Devices 215 

10 Video and Audio 237 

11 Networking 271 

12 Operating System Installation and Diagnostic Testing 299 

13 Tools and Techniques 309 

14 Connector Quick Reference 317 

Index 329

Contents 

1 General Technical Reference 1 

PC Subsystem Components Quick Reference 1 

The Motherboard and Its Components 2 

Understanding Bits, Nibbles, and Bytes 3 

Standard Capacity Abbreviations and Meanings 3 

Glossary of Essential Terms 5 

PC99 Color Standards 10 

Hexadecimal/ASCII Conversions 10 

2 System Components and Configuration 19 

Processors and Their Data Bus Widths 19 

Differences Between PC/XT and AT Systems 20 

Intel and Compatible Processor Specifications 21 

Troubleshooting Processor Problems 27 

Motherboard Form Factors 29 

Baby-AT Motherboard 30 

LPX Motherboard 31 

ATX Motherboard 31 

NLX Motherboard 32 

Which Motherboard Is Which? 32 

PC99 Color-Coding for Ports 33 

Power Supplies 34 

LPX Versus ATX Power Supplies 34 

Power Connectors for the Drive(s) 36 

Quick-Reference Chart for Troubleshooting Power 

Supplies 37 

Memory Types 38 

30-Pin SIMM 39 

72-Pin SIMM 39 

DIMMs 40 

RDRAM 40 

DDR SDRAM 41 

Parity Versus Non-Parity Memory 42 

Requirements for ECC Memory Use 43 

Using the Divide by 3 Rule to Determine Parity 

Support 43 

Using the Divide by 9 Rule to Determine Parity 

Support 43 

Expanding Memory on a System 44 

Memory Troubleshooting 45 

Memory Usage Within the System 46 

Hardware and Firmware Devices That Use Memory 

Addresses 46 

Using Memory Addresses Beyond 1MB (0FFFFF) 49 

Determining Memory Address Ranges in Use 49

vi 

Contents 

Other Add-On Card Configuration Issues 50 

IRQs 50 

DMA 52 

Determining Actual IRQ and DMA Usage 52 

I/O Port Addresses 54 

Determining Actual I/O Address Ranges in Use 57 

Troubleshooting Add-on Card Resource Conflicts 57 

Expansion Slots 62 

ISA 62 

EISA—A 32-bit Version of ISA 62 

VL-Bus—A Faster 32-Bit Version of ISA 62 

PCI 66 

AGP 66 

3 BIOS Configurations and Upgrades 69 

What the BIOS Is and What It Does 69 

When a BIOS Update Is Necessary 69 

Specific Tests to Determine Whether Your BIOS Needs 

an Update 70 

Fixing BIOS Limitations—BIOS Fixes and Alternatives 

70 

How BIOS Updates Are Performed 71 

Where BIOS Updates Come From 71 

Precautions to Take Before Updating a BIOS 72 

How to Recover from a Failed BIOS Update Procedure 73 

Plug-and-Play BIOS 74 

PnP BIOS Configuration Options 75 

When to Use the PnP BIOS Configuration Options 77 

Other BIOS Troubleshooting Tips 77 

Soft BIOS CPU Speed and Multiplier Settings 78 

Determining Which BIOS You Have 79 

Determining the Motherboard Manufacturer for BIOS 

Upgrades 79 

Identifying Motherboards with AMI BIOS 79 

Identifying Motherboards with Award BIOS 81 

Identifying Motherboards with Phoenix or Microid 

Research BIOS 82 

Accessing the BIOS Setup Programs 82 

How the BIOS Reports Errors 83 

BIOS Beep Codes and Their Purposes 83 

AMI BIOS Beep Codes 84 

Award BIOS Beep Codes 84 

Phoenix BIOS Beep Codes 85 

IBM BIOS Beep and Alphanumeric Error Codes 85 

Microid Research Beep Codes 86 

Reading BIOS Error Codes 88 

Onscreen Error Messages 88 

Interpreting Error Codes and Messages 88 

BIOS Configuration Worksheet 89 

4 SCSI and IDE Hard Drives and Optical Drives 93 

Understanding Hard Disk Terminology 93 

Heads, Sectors per Track, and Cylinders 93 

Hard Drive Heads 93 

Sectors per Track 93 

Cylinders 94

Contents vii 

IDE Hard Drive Identification 94 

Master and Slave Drives 95 

Breaking the 504MB (528-Million-Byte) Drive Barrier 97 

Using LBA Mode 98 

When LBA Mode Is Necessary—and When Not to Use 

It 98 

Problems with LBA Support in the BIOS 99 

Dangers of Altering Translation Settings 99 

Detecting Lack of LBA Mode Support in Your System 

100 

Using FDISK to Determine Compatibility Problems 

Between the Hard Disk and BIOS 101 

Getting LBA and Extended Int13h Support for Your 

System 102 

Determining Whether Your System Supports Extended 

Int13h 103 

Drive Capacity Issues in Microsoft Windows 95 and 98 

104 

Sources for BIOS Upgrades and Alternatives for Large IDE 

Hard Disk Support 105 

Standard and Alternative Jumper Settings 106 

Improving Hard Disk Speed 107 

Ultra DMA 108 

UDMA/66 and UDMA/100 Issues 108 

Bus-Mastering Chipsets for IDE 109 

Benefits of Manual Drive Typing 111 

Troubleshooting IDE Installation 112 

SCSI 113 

SCSI Types and Data Transfer Rates 113 

Single-Ended Versus Differential SCSI 114 

Low-Voltage Differential Devices 114 

Recognizing SCSI Interface Cables and Connectors 115 

8-Bit SCSI Centronics 50-Pin Connector 115 

SCSI-2 High-Density Connector 115 

SCSI-3 68-Pin P Cable 116 

RAID Array, Hot Swappable 80-Pin Connector 116 

SCSI Drive and Device Configuration 117 

SCSI Device ID 117 

SCSI Termination 119 

SCSI Configuration Troubleshooting 120 

Hard Disk Preparation 124 

Using FDISK 125 

Drive-Letter Size Limits 125 

Large Hard Disk Support 125 

Benefits of Hard Disk Partitioning 126 

FAT-32 Versus FAT-16 Cluster Sizes 127 

Converting FAT-16 Partition to FAT-32 128 

NTFS Considerations and Default Cluster Sizes 128 

How FDISK and the Operating System Create and Allocate 

Drive Letters 129 

Assigning Drive Letters with FDISK 130 

High-Level (DOS) Format 132 

Replacing an Existing Drive 133 

Drive Migration for MS-DOS Users 133 

Drive Migration for Windows 9x/Me Users 134 

XCOPY32 for Windows 9x Data Transfer 134

viii 

Contents 

Hard Disk Drive Troubleshooting and Repair 135 

Optical Drive Interface Types 137 

MS-DOS Command-Line Access to CD-ROM Drives for 

Reloading Windows 137 

Troubleshooting Optical Drives 138 

Failure Reading a CD 138 

Failure Reading CD-R and CD-RW Disks in a CD-ROM 

or DVD Drive 139 

IDE/ATAPI CD-ROM Drive Runs Slowly 139 

Trouble Using Bootable CDs 140 

5 Floppy, Removable, Tape, and Flash Memory 

Storage 143 

Floppy Drives 143 

Where Floppy Drives Fail—and Simple Fixes 144 

The Drive Cover 144 

The Stepper Motor 144 

Interface Circuit Boards 145 

Read/Write Heads 145 

Floppy Drive Hardware Resources 145 

Don’t Use a Floppy Drive While Running a Tape 

Backup 146 

Disk Drive Power and Data Connectors 146 

Floppy Drive Troubleshooting 148 

Common Floppy Drive Error Messages—Causes and 

Solutions 149 

Removable Storage Drives 150 

Sources for “Orphan” Drive Media, Repairs, Drivers, 

and Support 153 

Emergency Access to Iomega Zip Drive Files in Case of 

Disaster 153 

Troubleshooting Removable Media Drives 154 

Types of Flash Memory Devices 155 

Tape Backup Drives and Media 155 

Common Tape Backup Standards 155 

Travan Tape Drives and Media 156 

Proprietary Versions of Travan Technology 157 

Getting Extra Capacity with Verbatim QIC-EX Tape 

Media 157 

OnStream ADR Tape Drives and Media 158 

Choosing the Best High-Performance Backup 

Technology 159 

Successful Tape Backup and Restore Procedures 160 

Tape Drive Troubleshooting 161 

Tape Retensioning 164 

6 Serial Ports and Modems 165 

Understanding Serial Ports 165 

Pinouts for Serial Ports 166 

Current Loop Serial Devices and 25-Pin Serial Ports 

168 

UARTs 169 

UART Types 169 

Identifying Your System UART 170 

High-Speed Serial Ports (ESP and Super ESP) 171 

Upgrading the UART Chip 171

Serial Port Configuration 172 

Avoiding Conflicts with Serial Ports 173 

Troubleshooting I/O Ports in Windows 9x and Me 173 

Advanced Diagnostics Using Loopback Testing 174 

Loopback Plug Pinouts—Serial Ports 175 

Modems 176 

Modems and Serial Ports 176 

Modem Modulation Standards 176 

56Kbps Standards 177 

Upgrading from x2 or K56flex to V.90 with Flash 

Upgrades 178 

External Versus Internal Modems 180 

Modem Troubleshooting 180 

Pinouts for External Modem Cable (9-Pin at PC) 184 

Win98SE, Windows 2000, Windows Me, and ICS 184 

Requirements for ICS 185 

Overview of the Configuration Process 185 

7 Parallel Ports, Printers, Scanners, and Drives 189 

Parallel Port Connectors 189 

Parallel Port Performance 190 

Parallel Port Configurations 191 

Testing Parallel Ports 191 

Troubleshooting Parallel Ports 192 

Printers 193 

Hewlett-Packard PCL Versions 194 

Comparing Host-Based to PDL-Based Printers 195 

Printer Hardware Problems 196 

Printer Connection Problems 199 

Printer Driver and Application Problems 201 

Troubleshooting Parallel Port and Other Types of Scanners 202 

Parallel Port Drives 203 

8 USB and IEEE-1394 Ports and Devices 205 

Universal Serial Bus 205 

USB Port Identification 205 

Pinout for the USB Connector 205 

Typical USB Port Locations 206 

Adding USB Ports to Your Computer 206 

Prerequisites for Using USB Ports and Peripherals 207 

Troubleshooting USB Ports 207 

Using USB Hubs with Legacy (Serial, Parallel, and PS/2) 

Ports 209 

Online Sources for Additional USB Support 209 

USB 2.0 209 

IEEE-1394 210 

Adding IEEE-1394 Ports to Your Computer 210 

Comparing USB and IEEE-1394 211 

Troubleshooting IEEE-1394 Host Adapters and Devices 

212 

IEEE-1394 and Linux 213 

Online Sources for Additional IEEE-1394 Support 213 

9 Keyboards, Mice, and Input Devices 215 

Keyboard Designs 215 

The 101-Key Enhanced Keyboard 215 

101-Key Versus 102-Key Keyboards 215 

The 104-Key Windows Keyboard 215 

Contents ix

x 

Contents 

Using Windows Keys 215 

Keyboard-Only Commands for Windows 

9x/NT4/2000/Me with Any Keyboard 216 

Standard Versus Portable Keyboards 219 

Keyswitch Types 219 

Cleaning a Foam-Element Keyswitch 220 

Adjusting Keyboard Parameters in Windows 221 

Keyboard Layouts and Scan Codes 221 

Keyboard Connectors 225 

Keyboard Connector Signals 226 

USB Keyboard Requirements 227 

Keyboard Troubleshooting and Repair 227 

Keyboard Connector Voltage and Signal Specifications 229 

Keyboard Error Codes 229 

Mice and Pointing Devices 230 

Mouse Motion Detection Methods 230 

Pointing Device Interface Types 230 

Wireless Mouse Types 231 

Software Drivers for the Mouse 231 

Alternative Pointing Devices 232 

Mouse Troubleshooting 233 

10 Video and Audio 237 

Selecting a Monitor Size 237 

Monitor Resolution 238 

CRTs Versus LCDs 238 

Common Monitor Resolutions 238 

LCD Versus CRT Display Size 239 

Monitor Power Management Modes 239 

VGA Video Connector Pinouts 241 

VGA DB-15 Analog Connector Pinout 241 

Digital Flat Panel Pinouts 242 

Digital Visual Interface Pinouts 243 

VGA Video Display Modes 244 

Video RAM 246 

Memory, Resolution, and Color Depth 247 

Determining the Amount of RAM on Your Display Card 249 

Local-Bus Video Standards 249 

RAMDAC 251 

Refresh Rates 252 

Adjusting the Refresh Rate of the Video Card 252 

Comparing Video Cards with the Same Chipset 253 

Setting Up Multiple Monitor Support in Windows 

98/Me/2000 253 

System Configuration Issues for Multiple-Monitor 

Support 256 

Video Card and Chipset Makers Model Reference 256 

3-D Chipsets 256 

Multimedia Devices 256 

Troubleshooting Video Capture Devices 257 

Testing a Monitor with Common Applications 258 

Audio I/O Connectors 260 

Connectors for Advanced Features 262

Contents xi 

Sound Quality Standards 263 

Configuring Sound Cards 263 

PCI Versus ISA Sound Cards 264 

Multifunction (Modem and Sound) Cards 264 

Troubleshooting Audio Hardware 265 

Hardware (Resource) Conflicts 265 

Detecting Resource Conflicts 265 

Most Common Causes of Hardware Conflicts with 

Sound Card 266 

Freeing Up IRQ 5 for Sound Card Use While Still 

Printing 267 

Other Sound Card Problems 267 

11 Networking 271 

Client/Server Versus Peer-to-Peer Networking 271 

Choosing Network Hardware and Software 272 

NIC 272 

UTP Cable 273 

Hub 273 

Software 273 

Network Protocols 275 

IP and TCP/IP 275 

Selecting a Network Data-Link Protocol (Specification) 276 

Network Cable Connectors 277 

Wire Pairing for Twisted-Pair Cabling 278 

Making Your Own UTP Cables 278 

Network Cabling Distance Limitations 280 

Cabling Standards for Fast Ethernet 281 

Specialized Network Options 281 

What About Home Networking? 281 

Wireless Networking Standards 282 

Wireless Network Configuration and Selection Issues 

284 

TCP/IP Network Protocol Settings 284 

TCP/IP Protocol Worksheet 285 

Troubleshooting Networks 287 

Troubleshooting Network Software Setup 287 

Troubleshooting Networks in Use 288 

Troubleshooting TCP/IP 289 

Direct Cable Connections 290 

Null Modem and Parallel Data-Transfer Cables 290 

Direct Connect Software 291 

Troubleshooting Direct Cable Connections 295 

12 Operating System Installation and Diagnostic 

Testing 299 

Installing an Operating System on an Empty Drive 299 

Installing MS-DOS 299 

Installing Windows 9x 300 

Installing Windows Me 300 

Installing Windows NT 4.0 or Windows 2000 301 

Upgrading an Operating System 302 

Installing to the Same Folder 302 

Installing to a Different Folder 302 

Installing to a Different Partition 302

xii 

Contents 

Checking for IRQ, DMA, I/O, and Memory Usage 302 

MS-DOS Using MSD 302 

Windows 9x/2000/Me 303 

Windows NT 4.0 304 

Software Toolkit 304 

13 Tools and Techniques 309 

General Information 309 

Hardware Tools and Their Uses 309 

Tools of the Trade—Drive Installation 310 

Tools of the Trade—Motherboard and Expansion Card 

Installation 311 

Tools of the Trade—External Device and Networking 

Installation 312 

Tools of the Trade—Data Transfer 313 

Tools of the Trade—Cleaning and Maintenance 314 

14 Connector Quick Reference 317 

Serial Ports and Cables 317 

Parallel Ports 318 

SCSI Ports 318 

USB and IEEE-1394 (FireWire) 319 

Video Connectors 321 

Video Ports 321 

Video Cables 322 

Sound Card Ports 323 

Sound Card External Ports 323 

Sound Card Internal Connectors 325 

Network and Modem Ports and Cables 325 

RJ-45 Port and Cable 325 

RJ-11 Port and Cable Connector 326 

Older Network Connectors 326 

Index 329

About the Authors 

Scott Mueller is president of Mueller Technical Research, an international 

research and corporate training firm. Since 1982, MTR has 

specialized in the industry’s longest running, most in-depth, accurate, 

and effective corporate PC hardware and technical training 

seminars, maintaining a client list that includes Fortune 500 companies, 

the U.S. and foreign governments, and major software and 

hardware corporations, as well as PC enthusiasts and entrepreneurs. 

His seminars have been presented to thousands of PC support professionals 

throughout the world. 

Scott Mueller has developed and presented training courses in all 

areas of PC hardware and software. He is an expert in PC hardware, 

operating systems, and data-recovery techniques. For more information 

about a custom PC hardware or data-recovery training seminar 

for your organization, contact Lynn at 

Mueller Technical Research 

21 Spring Lane 

Barrington Hills, IL 60010-9009 

Phone: (847) 854-6794 

Fax: (847) 854-6795 

Internet: scottmueller@compuserve.com 

Web: http://www.m-tr.com 

Scott has many popular books, articles, and course materials to his 

credit, including Upgrading and Repairing PCs, which has sold more 

than 2 million copies, making it by far the most popular PC hardware 

book on the market today. 

If you have questions about PC hardware, suggestions for the next 

edition of the book, or any comments in general, send them to 

Scott via email at scottmueller@compuserve.com. 

When he is not working on PC-related books or teaching seminars, 

Scott can usually be found in the garage working on performance 

projects. This year a Harley Road King with a Twin-Cam 95ci Stage 

III engine continues as the main project (it’s amazing how something 

with only two wheels can consume so much time and money 

), along with a modified 5.7L ‘94 Impala SS and a 5.9L Grand 

Cherokee (hotrod SUV).

Mark Edward Soper is president of Select Systems and Associates, 

Inc., a technical writing and training organization that has been in 

business since 1989. Select Systems specializes in revealing the hidden 

power and features in PCs, their hardware, and their software. 

Select Systems has developed training courses and manuals for computer 

training firms and industrial, manufacturing, and media 

clients in print, HTML, and Adobe Acrobat formats. 

Mark has taught computer troubleshooting and other technical 

subjects to thousands of students from Maine to Hawaii since 1992. 

He is an A+ Certified hardware technician and a Microsoft Certified 

Professional. He has been writing technical documents since the 

mid-1980s, and has contributed to several other Que books, including 

Upgrading and Repairing PCs, 11th and 12th Editions; Upgrading 

and Repairing Networks, 2nd Edition; and Special Edition Using 

Windows Millennium Edition. Mark co-authored the original edition 

of this book, and his first books on A+ Certification will be published 

after the revised A+ Certification Exams are released at the 

end of 2000. Watch for details about these and other book projects 

at the newly improved Que Web site at www.mcp.com. 

For more information about customized technical reference and 

training materials, contact 

Select Systems and Associates, Inc. 

1100 W. Lloyd Expy #104 

Evansville, IN 47708 

Phone: (812) 421-1170 

Fax: (812) 426-6138 

Email: mesoper@selectsystems.com 

Web: http://www.selectsystems.com 

Mark has been writing for major computer magazines since 

1990, with more than 125 articles in publications such as 

SmartComputing, PCNovice, PCNovice Guides, and the PCNovice 

Learning Series. His early work was published in WordPerfect 

Magazine, The WordPerfectionist, and PCToday. Many of Mark’s articles 

are available in back issue or electronically via the World Wide 

Web at www.smartcomputing.com. Select Systems maintains a subject 

index of all Mark’s articles at http://www.selectsystems.com. 

When he’s not sweating out a writing deadline, Mark enjoys life 

with his wife, Cheryl, a children’s librarian who is also a published 

writer. Their children (now 21, 20, 20, and 18) are all computer 

users, keeping him busy with their questions, and he also provides 

computer support to his local church. Mark still finds time to

watch, photograph, and (occasionally) ride trains. He’s using his 

years of experience with photography and computers to build a 

personal image archive, and he has also created archiving programs 

for a local university. 

Mark welcomes your comments and suggestions about this book. 

Send them to mesoper@selectsystems.com. 

About the Technical 

Editor 

Mark Reddin, MCSE, A+, is a Microsoft Certified Systems 

Engineer and an A+ Certified PC technician. In addition to his 

work as a Que technical editor, Mark provides consulting services 

for NT systems and business networks. He has enjoyed using computers 

at the hobbyist level since the days of the Atari 400. This 

interest led to a professional level of involvement and, after dabbling 

in programming, he discovered networking. He achieved his 

first certification from Microsoft in early 1998 and has worked as a 

configuration technician for a computer reseller as well as an NT 

specialist and general networking contractor.

Acknowledgments 

Mark would like to thank the following people: Scott Mueller, 

whose Upgrading and Repairing PCs has been on his “short list” of 

great computer books for more than 10 years and whose latest edition 

provided much of the material for this book; Jill Byus Schorr 

and Rick Kughen at Que, whose encouragement and guidance have 

helped make this book a success; Cheryl, who never stopped believing 

that I could write; and God, who gives all of us talents and abilities 

and cheers us on as we develop them.

Tell Us What You Think! 

As the reader of this book, you are our most important critic and 

commentator. We value your opinion and want to know what we’re 

doing right, what we could do better, what areas you’d like to see us 

publish in, and any other words of wisdom you’re willing to pass 

our way. 

As the associate publisher for this book, I welcome your comments. 

You can fax, email, or write me directly to let me know what you 

did or didn’t like about this book—as well as what we can do to 

make our books stronger. 

When you write, please be sure to include this book’s title and 

authors as well as your name and phone or fax number. I will carefully 

review your comments and share them with the authors and 

editors who worked on the book. 

Fax: 317-581-4666 

Email: hardware@mcp.com 

Mail: Macmillan USA 

201 West 103rd Street 

Indianapolis, IN 46290

Introduction 

If you’re a computer repair technician or student, you know 

just how crucial it is to have concise, yet detailed, technical specifications 

at your fingertips. It can mean the success or failure of 

your job. 

Unfortunately, most detailed hardware books are far too large to 

tote around in a briefcase, book bag, or in your back pocket—where 

you need them. 

Upgrading and Repairing PCs: Technician’s Portable Reference is the 

exception. This concise book provides just the information you 

need to upgrade or repair your PC, without weighing you down. 

Although you should consider this book to be a companion to 

Scott Mueller’s best-selling opus, Upgrading and Repairing PCs, you’ll 

also find that it stands quite well on its own. While much of the 

information is in the mother book, much of what is found here is 

presented in a boiled-down, easy-to-digest reference that will help 

you get the job done quickly and efficiently. You’ll also find that 

this portable reference contains some information not found in the 

main book—information that is specially geared to help the technician 

in the field. 

I recommend that you keep Upgrading and Repairing PCs, 12th 

Edition (ISBN 0-7897-2303-4) on your desk or workbench and 

Upgrading and Repairing PCs: Technician’s Portable Reference with your 

toolkit, so it’s ready to go with you anytime—whether it’s to a customer 

job site or a class.

Chapter 1 

General Technical 

Reference 

1 

PC Subsystem Components Quick 

Reference 

The following table lists the major PC subsystems and how they are 

configured. Use this table as a shortcut to the most likely place(s) 

to look for problems with these subsystems. Then, go to the appropriate 

chapter for more information. 

Table 1.1 Major PC Subsystems and Where to Configure Them 

How Configured and See Chapters 

Subsystem Components Controlled for Details 

Motherboard CPU, RAM, ROM, Jumper blocks (CPU) 2, 3 

expansion slots, BIOS (all others plus 

BIOS CPU on some systems) 

I/O ports Serial BIOS and operating 

system 

3, 6 

Parallel BIOS and operating 

system 

3, 7 

USB BIOS and operating 

system drivers 

3, 8 

PS/2 mouse MB jumper blocks 

or BIOS 

3, 9 

Keyboard BIOS 3, 9 

I/O devices Modem Driver software 6 

Sound card Driver software 10 

Input devices Keyboard, mouse, BIOS 9 

trackball, touchpad Driver software 9 

Scanner Driver software 7 

Standard 

mass storage 

Floppy BIOS 5 

IDE BIOS and jumper blocks 4 

Add-on CD-ROM, Zip, Jumper blocks and 4 

mass storage LS-120, other 

removable media 

driver software 

SCSI Jumper blocks and 

add-on BIOS card or 

driver software 

4

2 

Table 1.1 Major PC Subsystems and Where to Configure Them 

Contiuned 

Chapter 1—General Technical Reference 

How Configured and See Chapters 

Subsystem Components Controlled for Details 

Tape backup Jumper blocks and 

tape backup 

software 

4, 5 

Display Video card BIOS (basic features), 10 

and monitor operating system 

(advanced features) 

Power supply (same) Autoselected voltage 

or slider switch on 

unit; on/off switch 

2 

The Motherboard and Its 

Components 

Figure 1.1 shows a typical motherboard with its major components 

labeled as it would appear before installation in a system. 

Figure 1.1 A typical ATX motherboard (overhead view). 

Figure 1.2 shows the ports on a typical ATX motherboard as they 

would be seen from the rear of the system.

Understanding Bits, Nibbles, and Bytes 3 

Figure 1.2 Ports on the rear of a typical ATX motherboard. 

Understanding Bits, Nibbles, and 

Bytes 

The foundation of all memory and disk size calculations is the byte. 

When storing plain-text data, a byte equals one character. 

Data can also be stored or transmitted in portions of a byte. A bit 

equals 1/8 of a byte, or, in other words, a byte equals eight bits. A 

nibble equals 1/2 of a byte, or four bits. Thus, two nibbles equal one 

byte. Keep the difference between bits and bytes in mind as you 

review the table of standard capacity abbreviations and meanings. 

Standard Capacity Abbreviations and Meanings 

Use the following table to translate megabytes, gigabytes, and the 

other abbreviations used to refer to memory and disk space into 

their decimal or binary values. 

Unfortunately, some parts of the computer industry use the decimal 

values, while others use the binary values. Typically, hard disk 

and other drive manufacturers rate their products in decimal 

megabytes or gigabytes. On the other hand, the ROM BIOS on 

most (but not all) systems and the MS-DOS and Windows FDISK 

programs use binary megabytes or gigabytes, thus creating an 

apparent discrepancy in disk capacity. RAM is virtually always calculated 

using binary values.

Table 1.2 Standard Abbreviations and Meanings 

Decimal 

Abbreviation Description Power Dec 

Kbit or Kb Kilobit 103 1,00 

K or KB Kilobyte 103 1,00 

Mbit or Mb Megabit 106 1,00 

M or MB Megabyte 106 1,00 

Gbit or Gb Gigabit 109 1,00 

G or GB Gigabyte 109 1,00 

Tbit or Tb Terabit 1012 1,00 

T or TB Terabyte 1012 1,00

Note 


For other conversion and reference tables, see the Technical 

Reference (found on the CD-ROM) of Upgrading and Repairing 

PCs, Twelfth Edition. 

Glossary of Essential Terms 

Table 1.3 Terms and Their Definitions 

Term Definition 

ACPI Advanced configuration and power interface; power management for 

all types of computer devices. 

AGP Accelerated graphics port; a fast dedicated slot interface between the 

video adapter or chipset and the motherboard chipset North Bridge; 

developed by Intel. AGP is 32 bits wide; runs at 66MHz; and can transfer 

1, 2, or 4 bits per cycle (1x, 2x, and 4x modes). 

APM Advanced power management; power management for hard drives 

and monitors. 

ATAPI AT attachment-packet interface; modified version of IDE that supports 

removable media and optical drives that use software drivers. Can 

coexist on the same cable with IDE hard drives. 

Beep code A series of one or more beeps used by the system BIOS to report 

errors. Beep codes vary by BIOS brand and version. 

BIOS Basic input/output system; a chip on the system board that controls 

essential devices, such as the keyboard, basic video display, floppy and 

hard drives, and memory. 

Cluster Also called allocation unit; the minimum disk space actually used by a 

file when it is stored; this size increases with larger drives due to the 

limitations of the FAT size. 

Color depth How many colors a video card can display at a given resolution; the 

higher the resolution, the more RAM required to display a given color 

depth. 

COM Communication port; also called serial port. 

Combo slot Also called shared slot; a pair of slots that share a single card bracket; 

only one of the two slots can be used at a time. 

Compact flash A type of flash memory device. 

CPU Central processing unit; the “brains” of a computer. 

CRT Cathode-ray tube; conventional TV-like picture tube display technology 

used on most desktop monitors. 

Data bus The connection that transmits data between the processor and the rest 

of the system. The width of the data bus defines the number of data 

bits that can be moved in to or out of the processor in one cycle. 

DCC Direct cable connection; Windows 9x/Me/2000 program that enables 

computers to link up through parallel or serial ports; Windows NT 4.0 

supports serial port linkups only.

6 


Table 1.3 Terms and Their Definitions Continued 


Device Manager Tab in the System Properties sheet for Windows 9x/2000/Me that 

enables you to view, change the configuration of, and remove system 

and add-on devices. 

DFP Digital flat panel; an early digital monitor standard replaced by DVI. 

DIMM Dual inline memory module; leading type of memory device from late 

1990s to present; current versions have 168 edge connectors. 

DMA Direct memory access; data transfer method used by some devices to 

bypass the CPU and go directly to and from memory; some ISA 

devices require the use of a specific DMA channel. 

DNS Domain name system; matches IP addresses to Web site and Web 

server names. 

DPMS Display Power Management Standard; the original power management 

standard for monitors. 

Drive geometry Combination of heads, sectors per track, and cylinders used to define 

an IDE drive in the system BIOS CMOS setup program. When a drive is 

moved to another system, the same drive geometry and translation 

settings must be used to enable the new system to read data from the 

drive. 

DVD Digital versatile disc; the emerging standard for home video and also a 

popular add-on for computers. 

DVI Digital video interface; the current digital monitor standard. 

ECC Error correcting code. A method of error correction; a type of system 

memory or cache that is capable of detecting and correcting some 

types of memory errors without interrupting processing. ECC requires 

parity-checked memory plus an ECC-compatible motherboard with 

ECC enabled. 

EISA Enhanced Industry Standard Architecture; a 32-bit version of ISA developed 

in 1989; found primarily in older servers; obsolete, but can be 

used for ISA cards. 

FAT File allocation table; on-disk directory that lists filenames, sizes, and 

locations of all clusters in a file. The size of the FAT limits the size of 

the drive. 

FAT-16 16-bit FAT supported by MS-DOS and Windows 95/95 OSR 1.x; drive 

letter limited to 2.1GB. 

FAT-32 32-bit FAT supported by Windows 95 OSR 2.x/98/Me; drive letter limited 

to 2.1TB. 

FCC ID Identification number placed on all computer hardware to certify it’s 

approved by the Federal Communications Commission. Use this number 

to locate drivers for some boards. 

Firmware “Software on a Chip”; general term for BIOS code on motherboards 

and in devices such as modems, printers, and others. 

Flash BIOS BIOS/firmware on systems or devices that can be updated through 

software. 

Flash memory Memory device whose contents can be changed electrically, but 

doesn’t require electrical power to retain its contents; used in digital 

cameras and portable music players.




HomePNA Home Phoneline Networking Alliance; a trade group that develops 

standards for networking over telephone lines within a home or small 

office. 

Host-based A type of printer in which the computer processes the image data; 

these printers are cheaper but less versatile than those containing a 

page-description or printer command language. 

Hub Device that accepts multiple connections, such as USB, 10BASE-T, and 

10/100 or Fast Ethernet hubs. 

I/O port Input/output port; used to communicate to and from motherboard or 

add-on devices. All devices require one or more I/O port address 

ranges, which must be unique to each device. 

ICS Internet connection sharing; a feature on Windows 98SE, Windows 

2000, and Windows Me that enables one computer to share its 

Internet connection with other Windows computers, including Win95 

and Win98 original versions. 

IDE Integrated Drive Electronics; also called AT Attachment. The 40-pin 

interface used on most hard drives, CD-ROMs, and internal versions of 

LS-120 SuperDisk and Iomega Zip drives. Drives must be jumpered as 

master, slave, or single. 

IEEE-1284 A series of parallel-port standards that include EPP and ECP high-speed 

bi-directional modes. 

IEEE-1394 Also called i.Link and FireWire; a very high-speed, direct-connect 

interface for high-performance storage, digital video editing, and scanning 

devices. 

IPX/SPX Standard protocols used on NetWare 3.x/4.x networks. 

IRQ Interrupt request line; used by devices to request attention from the CPU. 

ISA Industry Standard Architecture; a slot standard developed by IBM in 

1981 for 8-bit cards; enhanced by IBM in 1984 for 16-bit cards; now 

obsolete, although most systems have one or two on board. 

KDE K Desktop Environment; a popular GUI for Linux. 

LAN Local area network. 

LBA Logical block addressing; a BIOS-based method of remapping the normal 

drive geometry to overcome the 504-megabyte/528.5-millionbyte 

limit imposed by normal IDE drive designs. Can also be 

implemented by add-on cards or software drivers. 

LCD Liquid crystal display; flat-panel display technology used on notebook 

and advanced desktop computers. 

Legacy Non plug-and-play (PnP) card; also can refer to serial and parallel ports. 

Local Bus A series of high-speed slot standards (VL-Bus, PCI, and AGP) for video 

that bypass the slow ISA bus. 

Loopback A method of testing ports that involves sending data out and receiving 

data back through the same port; implemented with loopback plugs 

that loop send lines back to receive lines. 

LPT Line printer port; also called parallel port. 

LS-120 Also called SuperDisk; a 3.5'' drive and disk made by Imation (originally 

3M) with 120MB capacity. Drive can also read/write/format standard 

1.44MB 3.5'' media.

8 




MCA Micro Channel Architecture; a 16/32-bit slot standard developed by 

IBM in 1987 for its PS/2 models. Never became popular outside IBM 

circles; obsolete and incompatible with any other standard. 

Memory bank Amount of memory (in bits) equal to the system bus of a specific CPU. 

The number of memory modules to achieve a memory bank on a given 

system varies with the CPU and the memory types the system can use. 

Memory stick A type of flash memory device developed by Sony for use in its camera 

and electronic products. 

Mwave A series of IBM-made multifunction cards that combine sound and 

modem functions. 

NetBEUI Microsoft version of NetBIOS network protocol; can be used for small, 

non-routable workgroup networks. 

NIC Network interface card; connects your computer to a LAN (local area 

network). 

Parity A method of error checking in which an extra bit is sent to the receiving 

device to indicate whether an even or odd number of binary 1 bits was 

transmitted. The receiving unit compares the received information with 

this bit and can obtain a reasonable judgment about the validity of the 

character. Parity checking was used with many early memory chips and 

SIMMs, but is now used primarily in modem and serial port configuration. 

Parity error An error displayed when a parity check of memory reveals incorrect 

values were stored; the system halts and all unsaved work is lost. 

PC Card Current term for former PCMCIA card standard used in notebook computers. 

PC/AT Systems using an 80286 or better CPU; these have a 16-bit or wider 

data bus. 

PC/XT Systems using an 8088 or 8086 CPU; these have an 8-bit data bus. 

PCI Peripheral Component Interconnect; a 32/64-bit slot standard developed 

by Intel in 1992; 32-bit version used in all PCs from mid-1990s 

onward for most add-on cards; 64-bit version found in some servers. 

PCL Printer Control Language; a series of printer control commands and 

routines used by Hewlett-Packard on its LaserJet printers. 

PCMCIA Personal Computer Memory Card International Association; original 

term for what are now called PC Cards; primarily used in notebook 

computers. Some use PCMCIA/PC Card to avoid confusion with regular 

add-on cards for desktop computers. 

PDL Page Description Language; general term for any set of printer commands, 

such as PCL or PostScript. 

Peer server Computer that can be used as a client and also shares printers, folders, 

and drives with other users. 

PIO Programmed input/output; a series of IDE data-transfer rates that 

enable faster data throughput. Both the drive and interface must support 

the same PIO mode for safety. 

PnP Plug-and-Play; the combination of add-on device, BIOS, and operating 

system (OS) that enables the OS to detect, install software for, and 

configure the device. PnP is supported by Windows 9x/Me/2000. 

POST Power on self test; a test performed by the system BIOS during system 

startup.




PostScript Adobe’s sophisticated printer language used in laser and inkjet printers 

designed for graphic arts professionals. 

QIC Quarter-Inch Committee; the standards body responsible for most 

tape drive standards used by PC clients and small network servers. 

QIC-EX Extra-capacity cartridges developed for some QIC, QIC-Wide, and 

Travan drives by Verbatim. 

Register size Number of bits of data the CPU can process in a single operation. 

Resolution Combination of horizontal and vertical pixels in an image; larger monitors 

support higher resolutions. 

ROM BIOS Read-only memory BIOS; older BIOS chips that were socketed and 

could be updated only by being physically replaced. 

RS-232 Diverse serial port standard with many different device-specific 

pinouts; supports both 9-pin and 25-pin ports. 

Scan codes Hexadecimal codes transmitted by the keyboard when keys are struck; 

must be converted to ASCII for display onscreen. 

SCSI Small computer system interface; a family of high-performance interfaces 

used on high-speed hard drives, optical drives, scanners, and 

other internal and external devices. Each device must have a unique ID 

number. 

SIMM Single Inline Memory Module; common type of memory device from 

late 1980s to mid-1990s; can have 30 or 72 edge connectors. 

SmartMedia A type of flash memory device. 

SoundBlaster Creative Labs’ longtime family of sound cards; the de facto standard 

for DOS-based audio. 

TCP/IP Transmission Control Protocol/Internet Protocol; the protocol of the 

World Wide Web and the Internet. 

Travan A family of tape drives and media developed from QIC and QIC-Wide 

standards by Imation (originally 3M). 

UART Universal Asynchronous Receive/Transmit chip; the heart of a serial 

port or hardware-based modem. 

UDMA Ultra DMA; a series of IDE data transfer rates that use DMA for even 

faster performance. Most effective when combined with bus-mastering 

hard disk host adapter driver software. 

USB Universal Serial Bus; a high-speed, hub-based interface for pointing, 

printing, and scanning devices. 

UTP Unshielded twisted-pair cable, such as Category 5 used with 10/100 

Ethernet. 

v.90 Current 56Kbps high-speed, dial-up modem standard; replaced x2 and 

K56flex. 

v.92 New version of v.90 due in late 2000; supports call waiting and faster 

uploading. 

VESA Video Electronic Standards Association; trade group of monitor and 

video card makers that develops various display and power management 

standards. 

VGA Video graphics adapter; a family of analog display standards that support 

16 or more colors and 640×480 or higher resolutions.

10 




VL-Bus VESA Local-Bus; a slot standard based on ISA that added a 32-bit connector 

to ISA slots in some 486 and early Pentium models; obsolete, 

but can be used for ISA cards. 

Windows keys Keys beyond the normal keyboard’s 101 keys that perform special 

tasks in Windows 9x/NT4/2000/Me. 

WINS Windows Internet Naming Service; matches IP addresses to computers 

on a Windows network. 

x86 All processors that are compatible with Intel CPUs from the 8086/88 

through the newest Pentium IIIs and Celerons. Can refer to both Intel 

and non-Intel (AMD, VIA/Cyrix) CPUs. 

PC99 Color Standards 

Table 1.4 PC99 Color Coding Standards for Ports 

Port Type Color 

Analog VGA (DB15) Blue 

Audio line in Light blue 

Audio line out Lime green 

Digital monitor (DFP) White 

IEEE-1394 (i.Link, FireWire) Grey 

Microphone Pink 

MIDI/game port Gold 

Parallel port Burgundy 

Serial Port Teal or turquoise 

Speaker out (subwoofer) Orange 

Right-to-left speaker Brown 

USB Black 

Video out 

SCSI, network, telephone, 

Yellow 

modem, and so on None 

PS/2 Keyboard Purple 

PS/2 Mouse Green 

Hexadecimal/ASCII Conversions 

Use Table 1.5 to look up the various representations for any character 

you see onscreen or want to insert into a document. You can 

use the Alt+keypad numbers to insert any character into an ASCII 

document you create with a program such as Windows Notepad or 

MS-DOS’s Edit.

Table 1.5 Hexadecimal/ASCII Conversions 

Dec Hex Octal Binary Name Character 

0 00 000 0000 0000 blank 


1 01 001 0000 0001 happy face A 

2 02 002 0000 0010 inverse happy face B 

3 03 003 0000 0011 heart ♥ 

4 04 004 0000 0100 diamond ♦ 

5 05 005 0000 0101 club ♣ 

6 06 006 0000 0110 spade ♠ 

7 07 007 0000 0111 bullet • 

8 08 010 0000 1000 inverse bullet H 

9 09 011 0000 1001 circle ο 

10 0A 012 0000 1010 inverse circle • 

11 0B 013 0000 1011 male sign K 

12 0C 014 0000 1100 female sign L 

13 0D 015 0000 1101 single note M 

14 0E 016 0000 1110 double note N 

15 0F 017 0000 1111 sun O 

16 10 020 0001 0000 right triangle P 

17 11 021 0001 0001 left triangle Q 

18 12 022 0001 0010 up/down arrow ↕ 

19 13 023 0001 0011 double exclamation ! 

20 14 024 0001 0100 paragraph sign 

21 15 025 0001 0101 section sign § 

22 16 026 0001 0110 rectangular bullet ■ 

23 17 027 0001 0111 up/down to line ↕ 

24 18 030 0001 1000 up arrow ↑ 

25 19 031 0001 1001 down arrow ↓ 

26 1A 032 0001 1010 right arrow → 

27 1B 033 0001 1011 left arrow ← 

28 1C 034 0001 1100 lower left box ¿ 

29 1D 035 0001 1101 left/right arrow ↔ 

30 1E 036 0001 1110 up triangle d 

31 1F 037 0001 1111 down triangle e 

32 20 040 0010 0000 space Space 

33 21 041 0010 0001 exclamation point ! 

34 22 042 0010 0010 quotation mark “ 

35 23 043 0010 0011 number sign #

12 


Table 1.5 Hexadecimal/ASCII Conversions Continued 


36 24 044 0010 0100 dollar sign $ 

37 25 045 0010 0101 percent sign % 

38 26 046 0010 0110 ampersand & 

39 27 047 0010 0111 apostrophe ‘ 

40 28 050 0010 1000 opening parenthesis ( 

41 29 051 0010 1001 closing parenthesis ) 

42 2A 052 0010 1010 asterisk * 

43 2B 053 0010 1011 plus sign + 

44 2C 054 0010 1100 comma , 

45 2D 055 0010 1101 hyphen or minus sign - 

46 2E 056 0010 1110 period . 

47 2F 057 0010 1111 slash / 

48 30 060 0011 0000 zero 0 

49 31 061 0011 0001 one 1 

50 32 062 0011 0010 two 2 

51 33 063 0011 0011 three 3 

52 34 064 0011 0100 four 4 

53 35 065 0011 0101 five 5 

54 36 066 0011 0110 six 6 

55 37 067 0011 0111 seven 7 

56 38 070 0011 1000 eight 8 

57 39 071 0011 1001 nine 9 

58 3A 072 0011 1010 colon : 

59 3B 073 0011 1011 semicolon ; 

60 3C 074 0011 1100 less-than sign < 

61 3D 075 0011 1101 equal sign = 

62 3E 076 0011 1110 greater-than sign > 

63 3F 077 0011 1111 question mark ? 

64 40 100 0100 0000 at sign @ 

65 41 101 0100 0001 capital A A 

66 42 102 0100 0010 capital B B 

67 43 103 0100 0011 capital C C 

68 44 104 0100 0100 capital D D 

69 45 105 0100 0101 capital E E 

70 46 106 0100 0110 capital F F 

71 47 107 0100 0111 capital G G 

72 48 110 0100 1000 capital H H




73 49 111 0100 1001 capital I I 

74 4A 112 0100 1010 capital J J 

75 4B 113 0100 1011 capital K K 

76 4C 114 0100 1100 capital L L 

77 4D 115 0100 1101 capital M M 

78 4E 116 0100 1110 capital N N 

79 4F 117 0100 1111 capital O O 

80 50 120 0101 0000 capital P P 

81 51 121 0101 0001 capital Q Q 

82 52 122 0101 0010 capital R R 

83 53 123 0101 0011 capital S S 

84 54 124 0101 0100 capital T T 

85 55 125 0101 0101 capital U U 

86 56 126 0101 0110 capital V V 

87 57 127 0101 0111 capital W W 

88 58 130 0101 1000 capital X X 

89 59 131 0101 1001 capital Y Y 

90 5A 132 0101 1010 capital Z Z 

91 5B 133 0101 1011 opening bracket [ 

92 5C 134 0101 1100 backward slash \ 

93 5D 135 0101 1101 closing bracket ] 

94 5E 136 0101 1110 caret ^ 

95 5F 137 0101 1111 underscore _ 

96 60 140 0110 0000 grave ` 

97 61 141 0110 0001 lowercase A a 

98 62 142 0110 0010 lowercase B b 

99 63 143 0110 0011 lowercase C c 

100 64 144 0110 0100 lowercase D d 

101 65 145 0110 0101 lowercase E e 

102 66 146 0110 0110 lowercase F f 

103 67 147 0110 0111 lowercase G g 

104 68 150 0110 1000 lowercase H h 

105 69 151 0110 1001 lowercase I i 

106 6A 152 0110 1010 lowercase J j 

107 6B 153 0110 1011 lowercase K k 

108 6C 154 0110 1100 lowercase L l 

109 6D 155 0110 1101 lowercase M m 

110 6E 156 0110 1110 lowercase N n

14 




111 6F 157 0110 1111 lowercase O o 

112 70 160 0111 0000 lowercase P p 

113 71 161 0111 0001 lowercase Q q 

114 72 162 0111 0010 lowercase R r 

115 73 163 0111 0011 lowercase S s 

116 74 164 0111 0100 lowercase T t 

117 75 165 0111 0101 lowercase U u 

118 76 166 0111 0110 lowercase V v 

119 77 167 0111 0111 lowercase W w 

120 78 170 0111 1000 lowercase X x 

121 79 171 0111 1001 lowercase Y y 

122 7A 172 0111 1010 lowercase Z z 

123 7B 173 0111 1011 opening brace { 

124 7C 174 0111 1100 vertical line | 

125 7D 175 0111 1101 closing brace } 

126 7E 176 0111 1110 tilde ~ 

127 7F 177 0111 1111 small house f 

128 80 200 1000 0000 C cedilla Ç 

129 81 201 1000 0001 u umlaut ü 

130 82 202 1000 0010 e acute é 

131 83 203 1000 0011 a circumflex â 

132 84 204 1000 0100 a umlaut ä 

133 85 205 1000 0101 a grave à 

134 86 206 1000 0110 a ring å 

135 87 207 1000 0111 c cedilla ç 

136 88 210 1000 1000 e circumflex ê 

137 89 211 1000 1001 e umlaut ë 

138 8A 212 1000 1010 e grave è 

139 8B 213 1000 1011 I umlaut Ï 

140 8C 214 1000 1100 I circumflex Î 

141 8D 215 1000 1101 I grave Ì 

142 8E 216 1000 1110 A umlaut Ä 

143 8F 217 1000 1111 A ring Å 

144 90 220 1001 0000 E acute É 

145 91 221 1001 0001 ae ligature æ 

146 92 222 1001 0010 AE ligature Æ 

147 93 223 1001 0011 o circumflex ô



148 94 224 1001 0100 o umlaut ö 

149 95 225 1001 0101 o grave ò 

150 96 226 1001 0110 u circumflex û 

151 97 227 1001 0111 u grave ù 

152 98 230 1001 1000 y umlaut ÿ 

153 99 231 1001 1001 O umlaut Ö 

154 9A 232 1001 1010 U umlaut Ü 

155 9B 233 1001 1011 cent sign ¢ 

156 9C 234 1001 1100 pound sign £ 

157 9D 235 1001 1101 yen sign ¥ 

158 9E 236 1001 1110 Pt û 

159 9F 237 1001 1111 function ƒ 

160 A0 240 1010 0000 a acute á 

161 A1 241 1010 0001 I acute Í 

162 A2 242 1010 0010 o acute ó 

163 A3 243 1010 0011 u acute ú 

164 A4 244 1010 0100 n tilde ñ 

165 A5 245 1010 0101 N tilde Ñ 

166 A6 246 1010 0110 a macron a _ 

167 A7 247 1010 0111 o macron o _ 

168 A8 250 1010 1000 opening question mark ¿ 

169 A9 251 1010 1001 upper-left box ⁄ 

170 AA 252 1010 1010 upper-right box ø 

171 AB 253 1010 1011 1/2 

172 AC 254 1010 1100 1/4 


173 AD 255 1010 1101 opening exclamation ¡ 

174 AE 256 1010 1110 opening guillemets « 

175 AF 257 1010 1111 closing guillemets » 

176 B0 260 1011 0000 light block ■ 

177 B1 261 1011 0001 medium block ■ 

178 B2 262 1011 0010 dark block ■ 

179 B3 263 1011 0011 single vertical ≥ 

180 B4 264 1011 0100 single right junction ¥ 

181 B5 265 1011 0101 2 to 1 right junction µ 

182 B6 266 1011 0110 1 to 2 right junction ∂ 

183 B7 267 1011 0111 1 to 2 upper-right ∑ 

184 B8 270 1011 1000 2 to 1 upper-right ∏ 

185 B9 271 1011 1001 double right junction π 

1 

/2 

1 

/4

16 




186 BA 272 1011 1010 double vertical ∫ 

187 BB 273 1011 1011 double upper-right ª 

188 BC 274 1011 1100 double lower-right º 

189 BD 275 1011 1101 1 to 2 lower-right Ω 

190 BE 276 1011 1110 2 to 1 lower-right æ 

191 BF 277 1011 1111 single upper-right ø 

192 C0 300 1100 0000 single lower-left ¿ 

193 C1 301 1100 0001 single lower junction ¡ 

194 C2 302 1100 0010 single upper junction ¬ 

195 C3 303 1100 0011 single left junction √ 

196 C4 304 1100 0100 single horizontal ƒ 

197 C5 305 1100 0101 single intersection ≈ 

198 C6 306 1100 0110 2 to 1 left junction ∆ 

199 C7 307 1100 0111 1 to 2 left junction « 

200 C8 310 1100 1000 double lower-left » 

201 C9 311 1100 1001 double upper-left … 

202 CA 312 1100 1010 double lower junction g 

203 CB 313 1100 1011 double upper junction 

204 CC 314 1100 1100 double left junction Ã 

205 CD 315 1100 1101 double horizontal = 

206 CE 316 1100 1110 double intersection Œ 

207 CF 317 1100 1111 1 to 2 lower junction œ 

208 D0 320 1101 0000 2 to 1 lower junction – 

209 D1 321 1101 0001 1 to 2 upper junction — 

210 D2 322 1101 0010 2 to 1 upper junction “ 

211 D3 323 1101 0011 1 to 2 lower-left ” 

212 D4 324 1101 0100 2 to 1 lower-left ‘ 

213 D5 325 1101 0101 2 to 1 upper-left ’ 

214 D6 326 1101 0110 1 to 2 upper-left ÷ 

215 D7 327 1101 0111 2 to 1 intersection ◊ 

216 D8 330 1101 1000 1 to 2 intersection ÿ 

217 D9 331 1101 1001 single lower-right Ÿ 

218 DA 332 1101 1010 single upper-right ø 

219 DB 333 1101 1011 inverse space 

220 DC 334 1101 1100 lower inverse ‹ 

221 DD 335 1101 1101 left inverse › 

222 DE 336 1101 1110 right inverse fi 

g




223 DF 337 1101 1111 upper inverse fl 

224 E0 340 1110 0000 alpha α 

225 E1 341 1110 0001 beta β 

226 E2 342 1110 0010 Gamma Γ 

227 E3 343 1110 0011 pi π 

228 E4 344 1110 0100 Sigma Σ 

229 E5 345 1110 0101 sigma σ 

230 E6 346 1110 0110 mu µ 

231 E7 347 1110 0111 tau τ 

232 E8 350 1110 1000 Phi Φ 

233 E9 351 1110 1001 theta θ 

234 EA 352 1110 1010 Omega Ω 

235 EB 353 1110 1011 delta δ 

236 EC 354 1110 1100 infinity ∞ 

237 ED 355 1110 1101 phi φ 

238 EE 356 1110 1110 epsilon ε 

239 EF 357 1110 1111 intersection of sets Ô 

240 F0 360 1111 0000 is identical to apple 

241 F1 361 1111 0001 plus/minus sign ± 

242 F2 362 1111 0010 greater/equal sign Ú 

243 F3 363 1111 0011 less/equal sign Û 

244 F4 364 1111 0100 top half integral Ù 

245 F5 365 1111 0101 lower half integral ı 

246 F6 366 1111 0110 division sign ˆ 

247 F7 367 1111 0111 approximately ˜ 

248 F8 370 1111 1000 degree ¯ 

249 F9 371 1111 1001 filled-in degree ˘ 

250 FA 372 1111 1010 small bullet ˙ 

251 FB 373 1111 1011 square root ˚ 

252 FC 374 1111 1100 superscript n ¸ 

253 FD 375 1111 1101 superscript 2 ˝ 

254 FE 376 1111 1110 box ˛ 

255 FF 377 1111 1111 phantom space ˇ

2 

System 

Components and 

Chapter 2 

Configuration 

Processors and Their Data Bus 

Widths 

Table 2.1 Processors and Their Data Bus Widths 

Processor Data Bus Width 

Intel 8088 8-bit 



Intel 386SX 16-bit 

Intel 386DX 32-bit 

Intel 486SLC 16-bit 4 

Intel 486DLC 32-bit 4 

Intel 486 (all SX/DX series) 32-bit 

5, 6 

Intel 5X86 32-bit 

Intel Pentium 64-bit 

AMD K5 64-bit 1 

Intel Pentium MMX 64-bit 

AMD K6 64-bit 1 

Cyrix 6x86 64-bit 3 

Cyrix 6x86MX 64-bit 3 

Cyrix MII 64-bit 2 

Cyrix III 64-bit 7 

Intel Pentium Pro 64-bit 

Intel Pentium II 64-bit 

Intel Celeron 64-bit 

Intel Pentium III 64-bit 

Pentium II Xeon 64-bit 

Intel Pentium III Xeon 64-bit 

AMD Athlon 64-bit 

AMD Duron 64-bit 8 

Intel Itanium 64-bit 9 

Intel Willamette 64-bit 10 

1. Pin-compatible with Pentium. 

2. Cyrix is now a division of VIA; pin-compatible with Pentium.

20 

Chapter 2—System Components and Configuration 

3. Designed by Cyrix, produced for Cyrix by IBM. Chips might be marked as “Cyrix” or “IBM”; 

pin-compatible with Pentium. 

4. Designed by Cyrix, produced by Texas Instruments and others. Chips might be marked as 

“Cyrix” or “Texas Instruments.” Despite names, 486SLC was similar to 386SX, and 486DLC 

was similar to 386DX. 

5. Used as an upgrade to 486SX/DX-based systems. 

6. Different internally from AMD’s chip, but also used as an upgrade to 486SX/DX-based systems. 

7. Pin-compatible with Intel Celeron. 

8. Uses new Socket A technology. 

9. Future CPU model; will be capable of running new 64-bit instructions as well as 32-bit 

Windows instructions; previously code-named “Merced.” 

10. Future CPU model; is designed to run 32-bit Windows instructions. 

Differences Between PC/XT and AT 

Systems 

Systems that feature an 8-bit memory bus are called PC/XT systems 

after the pioneering IBM PC and IBM PC/XT. As you can see in 

Table 2.2, the differences between these systems and descendents of 

the IBM AT (16-bit memory bus and above) are significant. All 

modern systems fall into the AT category. 

Table 2.2 Differences Between PC/XT and AT Systems 

System Attributes 

PC/XT Type 8-Bit 16-, 32-, 64-Bit AT Type 

Supported processors All x86 or x88 286 or higher 

Processor modes Real Real, Protected, Virtual Real 2 

Software supported 16-bit only 16- or 32-bit 2 

Bus slot width 8-bit 16-, 32- 1 , and 64-bit 4 

Slot type ISA only ISA, EISA 1 , MCA, PC-Card, 

Cardbus 3 , VL-Bus 3 , PCI 3 , AGP 4 

Hardware interrupts 8 (6 usable) 16 (11 usable) 

DMA channels 4 (3 usable) 8 (7 usable) 

Maximum RAM 1MB 16MB/4GB1 or more 

Floppy controller 250 Kbit/sec 250, 300, 500, and 

speed 1,000 Kbit/sec 

Standard boot drive 360KB or 720KB 1.2M, 1.44MB, and 2.88MB 

Keyboard interface Unidirectional Bidirectional 

CMOS memory/clock None standard MC146818-compatible 

Serial-port UART 8250B 16450/16550A or better 

1. Requires 386DX-based system or above 

2. Requires 386SX-based system or above 

3. Requires 486SX-based system or above 

4. Requires Pentium-based system or above


Intel and Compatible Processor 

Specifications 

See Tables 2.3 and 2.4 to help determine the features of any CPU 

you encounter. It might be necessary to remove the heat sink or 

fan to see the processor markings on an older system, but many 

recent systems display CPU identification and speeds at startup. 

Table 2.4 shows the major Pentium-class CPUs made by companies 

other than Intel. The newest versions of these processors can often 

be used to upgrade an older Pentium—as long as proper voltage 

and system configuration information can be provided, either 

through adjusting the motherboard/BIOS settings or by purchasing 

an upgrade-type processor with third-party support. 

Footnotes for both tables follow Table 2.4.

22 


Table 2.3 Intel Processor Specifications 

Internal 

Register Data Bus 

Processor CPU Clock Voltage Size Width 

8088 1x 5v 16-bit 8-bit 

8086 1x 5v 16-bit 16-bit 

286 1x 5v 16-bit 16-bit 

386SX 1x 5v 32-bit 16-bit 

386SL 1x 3.3v 32-bit 16-bit 

386DX 1x 5v 32-bit 32-bit 

486SX 1x 5v 32-bit 32-bit 

486SX2 2x 5v 32-bit 32-bit 

487SX 1x 5v 32-bit 32-bit 

486DX 1x 5v 32-bit 32-bit 

486SL 2 1x 3.3v 32-bit 32-bit 

486DX2 2x 5v 32-bit 32-bit 

486DX4 2–3x 3.3v 32-bit 32-bit 

486Pentium OD 2.5x 5v 32-bit 32-bit 

Pentium 60/66 1x 5v 32-bit 64-bit 

Pentium 75-200 1.5–3x 3.3-3.5v 32-bit 64-bit 

Pentium MMX 1.5– 

4.5x 

1.8–2.8v 32-bit 64-bit 

Pentium Pro 2–3x 3.3v 32-bit 64-bit 

Pentium II 3.5– 

4.5x 

1.8–2.8v 32-bit 64-bit 

Celeron 3.5– 

4.5x 

1.8–2.8v 32-bit 64-bit 

Celeron A 3.5–7x 1.8–2v 32-bit 64-bit 

Pentium II PE3 3.5–6x 1.6v 32-bit 64-bit 

Pentium II Xeon 4–4.5x 1.8–2.8v 32-bit 64-bit 

Pentium III Slot1 4.5– 

7.5x 

1.8–2v 32-bit 64-bit 

Pentium III PGA370 4–7x 1.8–2v 32-bit 64-bit 

Pentium III Xeon 5–6.5x varies 32-bit 64-bit


L1 L2 

Max. Level 1 Cache L2 Cache Special 

Memory Cache Type Cache Speed Features 

1MB — — — — — 

1MB — — — — — 

16MB — — — — — 

16MB — — — Bus — 

16MB 0KB 1 WT — Bus — 

4GB — — — Bus — 

4GB 8KB WT — Bus — 

4GB 8KB WT — Bus — 

4GB 8KB WT — Bus FPU 


4GB 8KB WT — Bus FPU Opt. 



4GB 2x16KB WB — Bus FPU 



4GB 2x16KB WB — Bus FPU, MMX 

64GB 2x8KB WB 256KB, 

512KB, 

1MB 

Core FPU 

64GB 2x16KB WB 512KB 1/2 

Core 

FPU, MMX 

64GB 2x16KB WB 0KB — FPU, MMX 

64GB 2x16KB WB 128KB Core FPU, MMX 

64GB 2x16KB WB 256KB Core FPU, MMX 


1MB, 

2MB 

Core FPU, MMX 

64GB 2x16KB WB 512KB 1/2 

Core 

FPU, SSE 

64GB 2x16KB WB 256KB Core FPU, SSE 


1MB, 

2MB 

Core FPU, SSE

24 


Table 2.4 Intel-Compatible Pentium-Class Processors 

Internal 

Register Data Bus Max. 

Processor CPU Clock Voltage Size Width Memory 

AMD K5 1.5–1.75x 3.5v 32-bit 64-bit 4GB 

AMD K6 2.5–4.5x 2.2–3.2v 32-bit 64-bit 4GB 

AMD K6-2 2.5–6x 1.9–2.4v 32-bit 64-bit 4GB 

AMD K6-3 3.5–4.5x 1.8–2.4v 32-bit 64-bit 4GB 

AMD Athlon 5–10x10 (nee K7) 

1.6–1.8v 32-bit 64-bit 8TB 

AMD Athlon, 5–10x10 with performance 

enhancing 

cache (PEC) 

(code name 

“Thunderbird”) 

1.8v 32-bit 64-bit 8TB 

AMD Duron9 6x–7.5x10 “Thunderbird” 

1.6–1.8v 32-bit 64-bit 8TB 

Cyrix 6x86 2x 2.5–3.5v 32-bit 64-bit 4GB 

Cyrix 6x86MX/MII 2–3.5x 2.2–2.9v 32-bit 64-bit 4GB 

VIA Cyrix III 2.5–7x 2.2v 32-bit 64-bit 4GB 

Nexgen Nx586 2x 4v 32-bit 64-bit 4GB 

IDT Winchip 3–4x 3.3–3.5v 32-bit 64-bit 4GB 

IDT Winchip2/2A 2.33–4x 3.3–3.5v 32-bit 64-bit 4GB 

Rise mP6 2–3.5x 2.8v 32-bit 64-bit 4GB 

FPU = Floating-Point unit (internal math coprocessor) 

WT = Write-through cache (caches reads only) 

WB = Write-back cache (caches both reads and writes) 

Bus = Processor external bus speed (motherboard speed) 

Core = Processor internal core speed (CPU speed) 

MMX = Multimedia extensions, 57 additional instructions for graphics and sound processing 

3DNow = MMX plus 21 additional instructions for graphics and sound processing 

SSE = Streaming SIMD (Single Instruction Multiple Data) Extensions, MMX plus 70 additional 

instructions for graphics and sound processing 

1. The 386SL contains an integral-cache controller, but the cache memory must be provided outside 

the chip. 

2. Intel later marketed SL Enhanced versions of the SX, DX, and DX2 processors. These processors 

were available in both 5v and 3.3v versions and included power-management capabilities. 

3. The Enhanced mobile PII has an on-die L2 cache similar to the Celeron.


L1 L2 

Level 1 Cache Level 2 Cache Special 

Cache Type Cache Speed Features Similar to4 16+8KB WB — Bus FPU Pentium 

2x32KB WB — Bus FPU, MMX Pentium MMX 

2x32KB WB — Bus FPU, 3DNow Pentium MMX 

2x32KB WB 256KB Core FPU, 3DNow Pentium MMX 

2x64KB WB 512KB6 1/37 Core FPU, 3DNow Pentium III8 2x64KB WB 256KB Core FPU, 3DNow Pentium III 

2x64KB WB 64KB Core FPU, 3DNow Athlon PEC 

16KB WB — Bus FPU Pentium 

64KB WB — Bus FPU, MMX Pentium MMX 

64KB WB 256KB Core 

2x16KB WB — Bus FPU Pentium5 2x32KB WB — Bus FPU, MMX Pentium MMX 

2x32KB WB — Bus FPU, 3DNow AMD K6-2 

2x8KB WB — Bus FPU, MMX Pentium MMX 

4. These processors physically fit into the same Socket 7 used by Intel Pentium 75MHz and above 

models except as noted, but might require special chipsets or BIOS settings for best operation. 

Check with motherboard and chip mfr. before installing them in place of your existing 

Pentium-class chip. 

5. Pentium-class performance, but unique, non-standard pinout. 

6. Cache size for initial shipments (3rd Q 1999). Athlon designed it to allow cache sizes up to 

8MB. 

7. Athlon’s cache interface is designed to handle variable speed ratios, so later versions can run 

L2 cache more quickly. 

8. Athlon uses new AMD Slot A, physically similar to Slot 1 but with a different electrical pinout. 

9. Duron and “Thunderbird” versions of Athlon use new Socket A. 

10. Clock Multipliers listed based on 100MHz system bus (FSB) speeds; although Athlon and 

Duron use 200MHz bus, memory for these systems runs at PC100 or PC133 speeds, depending 

on the processor model.

26 


Use Tables 2.5 and 2.6 to help determine which processors may fit 

in place of your existing CPU. Note that a replacement CPU must 

have the same pinout, the same electrical requirements, and be 

compatible with your motherboard. Many vendors sell upgradecompatible 

processor versions, which have been modified from 

their original forms by adding a voltage regulator and other support 

options. 

Table 2.5 Intel and Compatibles 486/Pentium-Class CPU Socket 

Types and Specifications 

Socket Supported 

Number Pins Pin Layout Voltage Processors 

Socket 1 169 17×17 PGA 5v 486 SX/SX2, DX/DX21 , 

DX4 OverDrive 

Socket 2 238 19×19 PGA 5v 486 SX/SX2, DX/DX21 , 

DX4 OverDrive, 486 

Pentium OverDrive 

Socket 3 237 19×19 PGA 5v/3.3v 486 SX/SX2, DX/DX2, 

DX4, 486 Pentium 

OverDrive, AMD 5x86, 

Cyrix 5x86 

Socket 4 273 21×21 PGA 5v Pentium 60/66, 

OverDrive 

Socket 5 320 37×37 SPGA 3.3/3.5v Pentium 75-133, 

OverDrive 

Socket 62 235 19×19 PGA 3.3v 486 DX4, 486 Pentium 

OverDrive 

Socket 7 321 37×37 SPGA VRM Pentium 75-233+, MMX, 

OverDrive, AMD K5/K6, 

Cyrix M1, VIA Cyrix MII 

Socket 8 387 dual pattern SPGA Auto VRM Pentium Pro 

PGA370 370 37×37 SPGA 2.0v Celeron, Pentium III, VIA 

Cyrix III 

Slot 1 242 Slot Auto VRM Pentium II/III, Celeron 

Slot 2 330 Slot Auto VRM Pentium II Xeon/ 

Pentium III Xeon 

Slot A 242 Slot Auto VRM AMD Athlon (K7) SECC 

Socket A 462 SPGA Auto VRM AMD Duron/AMD 

Athlon PGA 

1. Non-overdrive DX4 or AMD 5x86 also can be supported with the addition of an aftermarket 

3.3v voltage-regulator adapter. 

2. Socket 6 was a paper standard only and was never actually implemented in any systems. 

PGA = Pin Grid Array. 

SPGA = Staggered Pin Grid Array. 

VRM = Voltage Regulator Module.

Table 2.6 lists the fastest processors you can install according to the 

socket type in your system. Note that newer socket designs allow 

faster processors, but that the bus speed and clock multiplier settings 

of your motherboard are also limiting factors for some CPU 

types. 

Table 2.6 Maximum Processor Speeds by Socket 

Socket Type Fastest Processor Supported 

Socket 1 5x86-133MHz with 3.3v adapter 

Socket 2 5x86-133MHz with 3.3v adapter 

Socket 3 5x86-133MHz 

Socket 4 Pentium OverDrive 133MHz 

Socket 5 Pentium MMX 233MHz or AMD K6 with 2.8v adapter 

Socket 7 AMD K6-2 up to 550MHz, K6-III up to 500MHz 

Socket 8 Pentium Pro OverDrive (333MHz Pentium II performance) 

Slot 1 Celeron 400MHz (66MHz bus) 

Slot 1 Pentium III 850MHz (100MHz bus) 

Slot 1 Pentium III 1.0GHz (133MHz bus) 

Slot 2 Pentium III Xeon 550MHz (100MHz bus) 

Slot 2 Pentium III Xeon 866MHz (133MHz bus) 

Socket 370 Celeron 600MHz (66MHz bus) 

Troubleshooting Processor Problems 27 

Socket 370 Pentium III 933MHz (100MHz bus) 

Slot A 1GHz AMD Athlon (K7) (200MHz bus), 1GHz AMD Athlon PEC 

(Thunderbird) 

Socket A 750MHz AMD Duron (200MHz bus), 1GHz AMD Athlon PEC 

(Thunderbird) 

Troubleshooting Processor 

Problems 

Table 2.7 provides a general troubleshooting checklist for processorrelated 

PC problems.

28 


Table 2.7 Troubleshooting Processor-Related Problems 

Problem 

Identification Possible Cause Resolution 

System is dead, no Power cord failure. Plug in or replace power cord. 

cursor, no beeps, Power cords can fail even 

or no fan. though they look fine. 

Power supply Replace the power supply. Use 

failure. a known, good spare for testing. 

Motherboard Replace motherboard. Use a 

failure. known, good spare for testing. 

Memory failure. Remove all memory except one 

bank and retest. If the system still 

won’t boot, replace bank 1. 

System is dead, no All components Check all peripherals, especially 

beeps, or locks up either not installed memory and graphics adapter. 

before POST begins. or incorrectly installed. 

Reseat all boards and socketed 

components, such as CPUs and 

memory modules. 

System beeps on Improperly seated Reseat or replace graphics adapter. 

startup, fan is or failing graphics Use known, good spare for testing. 

running, no 

cursor onscreen. 

adapter. 

Locks up during Poor heat Check CPU heat sink/fan; replace if 

or shortly after dissipation. necessary, using one with a higher 

POST. capacity. 

Use thermal paste between 

fan/heatsink and CPU as directed 

by heatsink and CPU vendors. 

Improper voltage Set motherboard for proper core 

settings. processor voltage. 

Wrong motherboard 

bus speed. 

Set motherboard for proper speed. 

Wrong CPU clock Jumper motherboard for proper 

multiplier. clock multiplier. 

Improper CPU identification 

during POST. 

Old BIOS. Update BIOS from manufacturer. 

Board not Check manual and jumper board 

configured properly. according to proper bus and multiplier 

settings. 

If board is jumperless, adjust bus 

and multiplier in BIOS.

Table 2.7 Troubleshooting Processor-Related Problems Continued 

Problem 

Identification Possible Cause Resolution 

Operating system Poor heat Check CPU fan; replace if 

will not boot. dissipation. necessary. May need higher capacity 

heat sink and thermal paste. 

Improper voltage Jumper motherboard for proper 

settings. core voltage. 

Wrong motherboard Jumper motherboard or adjust 

bus speed. BIOS settings to correct speed. 

Wrong CPU clock Jumper motherboard or adjust 

multiplier. BIOS settings to correct multiplier. 

Applications will Improper drivers or incompatible 

not install or run. hardware. Update drivers and 

check for compatibility issues. 

System appears Monitor turned Check monitor and power to 

to work but no off or failed. monitor. Replace with knownvideo 

is displayed good spare for testing. 

If, during POST, the processor is not identified correctly, your 

motherboard settings might be incorrect or your BIOS might need 

to be updated. Check that the motherboard is jumpered or configured 

correctly for the processor that you have, and make sure that 

you have the latest BIOS for your motherboard. 

If the system seems to run erratically after it warms up, try setting 

the processor to a lower speed. If the problem goes away, the 

processor might be defective or overclocked. 

Many hardware problems are really software problems in disguise. 

Be sure you have the latest BIOS for your motherboard and the latest 

drivers for your peripherals. Also, it helps to use the latest version 

of your given operating system because, normally, fewer 

problems will occur. 

Note 


For more information about processors, see Chapter 3 of 

Upgrading and Repairing PCs, 12th Edition, also published by Que. 

Motherboard Form Factors 

Although many PC users have extended the life span of their systems 

by changing the CPU, any system that will be kept for a long 

time could be a candidate for a motherboard replacement. Use the 

following charts to determine whether your system uses one of

30 


these standard form factors, which will allow you the choice of 

many vendors for a replacement. A replacement motherboard provides 

you with these benefits: 

• Access to faster, more advanced CPUs 

• “Free” updated BIOS with support for large hard drives; Y2K; 

and boot from LS-120, Zip, and CD-ROM drives 

• Newer I/O features, such as USB ports, UDMA-66 hard disk 

interfacing, and AGP video 

Baby-AT Motherboard 

Until mid-1996, this descendent of the original IBM/XT motherboard 

was the dominant design. Even though limited numbers of 

these motherboards are still available for use with both Pentiumclass 

and Pentium II/III/Celeron processors, the lack of built-in ports 

and cooling problems make this an obsolete design. If you are trying 

to upgrade a system that uses this motherboard design, consider 

purchasing a new ATX-style case, power supply, and motherboard. 

In addition, you should consider moving the CPU, RAM, drives, and 

cards from your existing system to the new box (see Figure 2.1). 

13.04" 

6.50" 

.34" 

.65" 

.45" 

3.75" 

.40" 

5.55" 

8.35" 

8.57" 

Figure 2.1 Baby-AT motherboard form factor dimensions. 

6.00"

LPX Motherboard 


Since 1987, many low-cost systems have used variations on this layout, 

which features a single slot used for a riser card. The expansion 

cards for video, audio, and so forth are connected to the riser card, 

not the motherboard. Most LPX systems use riser cards that mount 

the expansion slots parallel to the motherboard; some use a T-shaped 

riser card that keeps the expansion slots at their normal upright position. 

Additionally, most LPX systems have built-in video, audio, and 

other I/O ports. Unfortunately, because its details were never standardized, 

it is virtually impossible to upgrade. Systems with this 

motherboard are essentially disposable (see Figure 2.2). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2.2 Typical LPX system chassis and motherboard. 

 

 

 

 

ATX Motherboard 

Since mid-1996, the ATX motherboard has become the standard 

for most systems using non-proprietary motherboards (see Figure 

2.3). Similar to Baby-AT, it’s also an industry standard, and similar 

to LPX, it features built-in ports. Compared to both, though, it 

offers much greater ease of upgrading and servicing. ATX motherboards 

are rotated 90 degrees when compared to Baby-ATs and also 

use a different power supply for advanced power management features. 

Because of their built-in ports and differences in layout, ATX 

motherboards require an ATX case. ATX cases can also be used for 

Baby-AT motherboards, though. Figure 2.3 shows a full-size ATX 

layout; however, several smaller versions now exist, including 

mini-ATX, micro-ATX, and flex-ATX.

32 


Double high 

expandable I/O 

Full 

length slots 

Floppy/IDE 

connectors close 

to peripheral bays 

Figure 2.3 ATX system chassis layout and features. 

NLX Motherboard 

3 1/2" 

Bay 

Processor 

Single 

chassis fan 

CPU located 

near PSU 

Single power 

connector 

Easy to access 

SIMM memory 

The replacement for the old LPX low-profile motherboard is the 

NLX motherboard (see Figure 2.4). NLX also features built-in ports 

and a riser card, but its standard design means that replacement 

motherboards should be easier to purchase than those for LPX systems. 

A major advantage of NLX systems is that the motherboard is 

easy to remove for servicing through a side panel, a feature that 

makes NLX-based systems popular as corporate network client PCs. 

5 1/4" 

Bay 

Power 

Supply 

Figure 2.4 NLX motherboard and riser combination. 

Which Motherboard Is Which? 

Use Table 2.8 to help determine whether a system is a Baby-AT, an 

LPX, an ATX, or an NLX-based system.

Table 2.8 Comparison of Major Motherboard Form Factors 

Baby-AT LPX 

ATX/ 

Micro ATX1 NLX WTX 

Ports built No Yes Yes Yes No2 into chassis 

Riser card No Yes No Yes No 

Single row of 

ports at rear 

N/A Yes No No No 

Two rows of N/A No Yes Yes No3 ports at rear 

Slots on both 

sides of riser 

card 

N/A Opt N/A No N/A 

Riser card N/A Middle N/A Side near N/A 

location power 

on MB supply 

1. MicroATX motherboards can fit into ATX cases, but have fewer slots and are designed for 

socketed, rather than slot-based, processors. They also usually feature onboard audio and 

video, both of which are usually optional on ATX motherboards. 

2. WTX supports a FlexSlot design, which uses a single modified PCI slot for all standard ports. 

3. The layout of ports on the rear of a FlexSlot resembles the layout on the rear of an ATX or a 

MicroATX motherboard, but they are vertically oriented because they are attached to a 

FlexSlot. See www.wtx.org for more information. 

PC99 Color-Coding for Ports 

Microsoft and Intel have developed the following standardized 

color-coding of connectors for computers compliant with the PC99 

design standards. Use Table 2.9 to help you match non–color-coded 

peripherals with the correct external ports. 

Note 

Some systems, especially those built before 1999, might use a 

proprietary color scheme for ports. 

Check the inside front and back covers of this book for pictures of 

these ports. For color samples, see the following Web site: 

http://www.pcdesguide.com/documents/pc99icons.htm 

Table 2.9 PC99 Color-Coding Standards for Ports 


Analog VGA (DB15) Blue 

Audio line in Light blue 

Audio line out Lime green 

Digital monitor White 

PC99 Color-Coding for Ports 33

34 


Table 2.9 PC99 Color-Coding Standards for Ports Continued 


IEEE-1394 (i.Link, FireWire) Grey 

Microphone Pink 

MIDI/Gameport Gold 

Parallel port Burgundy 

Serial port Teal or turquoise 

Speaker out (subwoofer) Orange 

Right-to-left speaker Brown 

USB Black 

Video out Yellow 

SCSI, network, telephone, 

modem, and so on 

None 

Power Supplies 

Power supplies actually convert high-voltage AC (alternating current) 

into low-voltage DC (direct current) for use by PCs. Power 

supplies come in several form factors, and they also feature various 

motherboard connectors to correspond with the newer motherboard 

designs on the market. Table 2.10 illustrates which power 

supplies are most likely to be used with various motherboards. 

Table 2.10 Matching Power Supplies and Motherboards 

Motherboard Most Common PS Other PS Form 

Form Factor Form Factor Used Factors Used 

Baby-AT LPX style Baby-AT, AT/Tower, 

or AT/Desk 

LPX LPX style None 

ATX ATX style None 

MicroATX ATX style SFX style 

NLX ATX style None 

LPX Versus ATX Power Supplies 

Some motherboards are designed to handle either LPX or ATX 

power supplies. The ATX is the preferred design because it provides 

the lower voltage needed by today’s CPUs, offers foolproof installation, 

and also provides better cooling than older designs. 

Table 2.11 compares two of the more common power supply form 

factors used in computers today, and Figure 2.5 shows an LPX 

power supply.

Table 2.11 Comparing ATX and LPX Power Supplies 


Power Motherboard 

Supply Voltage Power Other 

Type Output Connectors Features Notes 

LPX 5v, 12v 2–6 pins Easy to reverse the 

each (P8/P9) plug due to poor keying 

ATX 3.3v, 5v, 12v 1–20 pins Keyed to go in only one 

way; allows hibernation via 

operating system or keyboard 

command 

86mm 

6mm 

64mm 

86mm 

16mm 

5 138mm 

7 

+ 

+ 

5 115mm 

150mm 

Figure 2.5 LPX form factor power supply. 

140mm 

+ 

+ 

30mm 

+5V 

G 

G 

+12V 

+5V 

G 

G 

+12V 

+5V 

G 

G 

+12V 

Table 2.12 breaks down the typical LPX power supply connector. 

6 

+5V 

G 

G 

+12V 

P.G. 

+5V 

+12V 

-12V 

G 

G 

G 

G 

-5V 

+5V 

+5V 

+5V

36 

Caution 


To get the cables oriented correctly, keep the ground wires 

(black) next to each other. Although most connectors are keyed 

to prevent improperly plugging them in, some connectors can 

easily be inserted incorrectly. This will cause your motherboard 

to be destroyed the first time you switch on the power and 

could possibly cause a fire. 

Table 2.12 Typical LPX Power Supply Connections 

Connector Voltage Standard Color/Notes 

P8-1 Power_Good (+5v) Orange 

P8-2 +5v Red 

P8-3 +12v Yellow 

P8-4 -12v Blue 

P8-5 Ground (0) Black 




P9-3 -5v White 

P9-4 +5v Red 

P9-5 +5v Red 

P9-6 +5v Red 

Power Connectors for the Drive(s) 

The connectors shown in Table 2.13 might not be labeled, but they 

easily can be distinguished by the four-wire cable and color-coding. 

The same colors are used for drive power connectors on ATX power 

supplies. Figure 2.6 shows an ATX power supply. 

Table 2.13 ATX Power Supply Color Coding 

Connector Voltage Standard Color/Notes 

P10-1 +12v Yellow 



P10-4 +5v Red

86mm 

6mm 

64mm 

86mm 

16mm 

5 138mm 

7 

+ 

+ 

140mm 

5 115mm 

150mm 

+ 

+ 

30mm 

6 

+5V 

G 

G 

+12V 

+5V 

G 

G 

+12V 

+5V 

G 

G 

+12V 

+5V 

G 

G 

+12V 


3.3V* 

11 1 

3.3V* 

12 2 

-12V 

3.3V* 

13 3 

COM 

COM 

14 4 

PS-ON 

5V 

15 5 

COM 

COM 

16 6 

COM 

5V 

17 7 

COM 

COM 

18 8 

-5V 

PW-OK 

5V 

19 9 

5VSB 

20 10 

5V 

12V 

*optional 

ATX Power connector pin out 

Figure 2.6 ATX form factor power supply used with both ATX and NLX 

systems. The pinout for the motherboard power is shown at lower right. 

Note the single square pin used for keying. 

Table 2.14 shows the pinout for the ATX motherboard power connector. 

Table 2.14 ATX Motherboard Power Supply Connections 

Color Signal Pin Pin Signal Color 

Orange +3.3v 11 1 +3.3v Orange 

Blue -12v 12 2 +3.3v Orange 

Black GND 13 3 GND Black 

Green PS_On 14 4 +5v Red 


Black GND 16 6 +5v Red 


White -5v 18 8 Power_Good Grey 

Red +5v 19 9 +5VSB 

(Standby) 

Purple 

Red +5v 20 10 +12v Yellow 

Quick-Reference Chart for Troubleshooting Power 

Supplies 

Table 2.15 Troubleshooting Power Supplies 

Symptom Cause(s) Tests and Solution(s) 

Overheating. Inadequate system cooling Check ventilation around system; 

clean system internally; check for 

missing slot covers. 

Higher load on system in Replace power supply with higher 

watts than power supply rated unit. 

rating

38 

Table 2.15 Troubleshooting Power Supplies Continued 

Symptom Cause(s) Tests and Solution(s) 

System reboots Incorrect power level on Use DC-voltage digital multimeter 

itself. Power_Good; can indicate (DMM) to test P8-1 (orange wire) 

overloaded power supply on LPX and older power supplies 

or otherwise bad unit or Pin 8 (gray wire) on ATX and 

newer power supplies; rated voltage 

is +5v; acceptable is +3.0v to 

+6.0v. 

Replace failed power supply with 

higher rated unit. 

Fan turns for Wrong voltage (PS set to Turn off system; reset PS to 

only a moment 220/230v in U.S.) correct voltage (110/115v in 

and then stops. U.S.) and restart. Using 220/230v 

power on a PS set for 110/115v 

will destroy it! 

Dead short in system Short can be caused by loose 

screws, failed hard drives, or addon 

cards. 

Turn off and unplug system; disconnect 

hard drive and see 

whether system starts. If system 

still fails, plug in drive and remove 

add-on card; repeat until each 

card and drive has been checked; 

also check Y-adapter cables 

because bad cables can cause 

shorts. 

Note 


Replace faulty component(s). 

For more information on power supplies, wattage ratings, and 

testing, see Chapter 21 of Upgrading and Repairing PCs, 12th 

Edition, published by Que. 

Memory Types 

RAM (random access memory) provides the work area that processors 

use to create and modify data. While RAM was sometimes 

found on expansion boards on old XT-class and early AT-class systems, 

all standard 486-based and Pentium-class systems have their 

memory modules attached to the motherboard. 

Memory modules come in two major forms: SIMMs and DIMMs. 

SIMM stands for single-sided inline memory module, and DIMM 

stands for dual-sided inline memory module. These terms refer to 

the pin configurations used on the module, rather than the location 

of the memory chips on the module.

The following features are common to all SIMMs: 

• Pins numbered from left to right 

• Same pins on both sides of the module 


Tip 

Note that all dimensions for both SIMMs and DIMMs in the following 

figures are in both inches and millimeters (in parentheses). 

30-Pin SIMM 

The 30-pin SIMM is the oldest type of memory module still in use 

(see Figure 2.7). It was popular on 386-based and early 486-based 

systems, but became obsolete with the rise of Pentium-class 64-bit 

CPUs. Although its capacities are extremely small compared to 

more modern memory designs, its unpopularity since the early 

1990s makes the 30-pin SIMM the most expensive memory type 

per megabyte. If you are still supporting systems that use this type 

of module, look for sources of used memory or replace the motherboard 

with one that uses newer, 72-pin SIMM or DIMM memory 

instead of buying new 30-pin modules. 

.250 (6.35) 

TYP. 

.080 (2.03) 

TYP. 

PIN 1 

3.505 (89.03) 

3.495 (88.77) 

.100 (2.54) 

TYP. 

.400 (10.16) 

TYP. 

.070 (1.78) 

TYP. 

.653 (16.59) 

.647 (16.43) 

.133 (3.38) 

TYP. 

.055 (1.40) 

.047 (1.19) 

.200 (5.08) 

MAX. 

Figure 2.7 A typical 30-pin SIMM. The one shown here is 9-bit, 

although the dimensions would be the same for 8-bit. 

72-Pin SIMM 

The 72-pin SIMM was the most popular for a number of years, but 

has now been superseded on newer systems by DIMM modules. 72pin 

SIMMs are commonly found on late-model 486-based systems, 

most Pentiums, and most early Pentium-compatible systems. 

Because these modules are also becoming very expensive per 

megabyte, try to salvage or swap memory to populate older systems 

rather than purchase new. 72-pin SIMMs can be either fast-page or 

extended data out (EDO). 486-class systems can use only fast-page 

SIMMs, but Pentium-class systems that use SIMMs can use either 

type. Fast-page and EDO SIMMs should not be mixed. Some

40 


systems require BIOS configuration to optimize performance if you 

install EDO memory (see Figure 2.8). 

.125 (3.18) 

TYP 

.250 

(6.35) 

.080 (2.03) 

PIN 1 

1.75 (44.45) TYP 

4.260 (108.20) 

4.240 (107.70) 

.250 (6.35) 

3.75 (95.25) 

Figure 2.8 A typical 72-pin SIMM, although the dimensions would be 

the same for 32-bit. 

DIMMs 

DIMMs became popular with the rise of the Pentium II/III/Celeron 

family of processors—AMD’s Athlon series—and can also be found 

on many late-model Pentium and “Super Socket 7” motherboards 

used with AMD K6-series and Cyrix 6x86MX/MII processors (see 

Figure 2.9). DIMMs are the most popular and fastest type of memory 

module in widespread use. Most DIMMs are Synchronous 

DRAM (SDRAM). On motherboards with both SIMM and DIMM 

sockets, SDRAMs cannot be used in conjunction with SIMMs, but 

the relatively rare EDO DIMMs can be used along with EDO 

SIMMs. 

.050 (1.27) 

TYP 

The following features are common to all DIMMs: 

• Three edge connectors of varying widths for positive keying 

.040 (1.02) 

TYP 

• Different pinouts on each side of the DIMM 

.079 (2.00) R 

(2X) 

.118 (3.00) R 

(2X) 

.118 (3.00) TYP 

.118 (3.00) 

TYP 

FRONT VIEW 

5.260 (133.80) 

5.240 (133.00) 

.250 (6.35) TYP 

1.661 (42.18) 

.039 (1.00)R (2X) 

.39 (1.27) 

2.625 (66.68) 

TYP 

PIN 1 (PIN 85 ON BACKSIDE) 

4.550 (115.57) 

.050 (1.27) 

TYP 

+ 

.133 (3.38) 

TYP 

.235 (5.97) 

MIN 

1.010 (25.65) 

.990 (25.15) 

.400 (10.16) 

TYP 

– 1.260 (32.00) 

1240 (31.50) 

.700 (17.7B) 

TYP 

.128 (3.25) 

.118 (3.00) (2x) 

PIN 84 (PIN 168 ON BACKSIDE) 

.350 (8.98) 

MAX 

.054 (1.37) 

.047 (1.19) 

.350 (8.89) 

MAX 

.054 (1.37) 

.046 (1.17) 

Figure 2.9 A typical 168-pin DIMM. The one shown here is 72-bit, 

although the dimensions would be the same for 64-bit. 

RDRAM 

The RDRAM, or Rambus DRAM, is a radical new memory design that 

is slowly appearing in high-end PC systems that use Intel chipsets. 

RDRAM differs from previous memory devices in that it provides 

multiple high-speed (800MHz), narrow-channel (16-bit–wide) data


transfers to and from a 128-bit memory bus instead of the slower 

(100MHz or 66MHz), 32-bit or 64-bit data transfers of SDRAM and 

previous memory types. 

RDRAM modules are called RIMMs (Rambus Inline Memory Module), 

and any unused RIMM slots on a motherboard must be filled with 

a continuity module to permit a continuous high-speed data pathway 

through the RIMMs (see Figure 2.10). Each RIMM represents 

multiple memory banks, and thus a single RIMM at a time can be 

added to a system—much the way installation of DIMMs works, 

although the memory types are not interchangeable. 

1.00 [0.039] 3.00 [0.118] 

Detail A 

4.00 [0.157] 

5.675 [0.2234] 

REF. 

A-1 

+ 

COMPONENT AREA 

(A SIDE) 

+ 

B-1 

133.35 +0.15 

-0.15 5.250+0.006 

-0.006 

+ 

Detail B 

1.00[0.039] 

11.50[0.453] 

4.50[1.772] 

45.00[1.777] 

27.50[1.083] 

45.00[1.772] 

+0.08 

55.18 

-0.08 

78.17[3.078] 

REF. 

2.172+0.003 

-0.003 

-A- 

+ 

+ 

COMPONENT AREA 

(B SIDE) 

+ 

+ 

+ 

B-92 

17.78 [0.700] 

0.85 [0.033] 

4.00 +0.15 

-0.15 0.157+0.006 

-0.006 

-B- 

A-92 

1.27 +0.10 

-0.10 

0.050 +0.004 

-0.004 

+0.10 

3.00 

-0.10 

0.80 +0.10 

Detail B 

-0.10 

TYP. 184 PLCS 

0.15 +0.10 

-0.10 

3XScale 

2.99 +0.05 

-0.05 

Capacitor 

CSP 

Note: Components 

Not Always Present 

on B side 

0.75-1.35 

[0.030-0.053] 

-C- 

+ 

3XScale 

Figure 2.10 Typical RDRAM bus layout, showing two RIMMs and one 

continuity module installed. 

DDR SDRAM 

Double Data Rate (DDR) SDRAM memory is an improved version of 

standard SDRAM in which data is transferred twice as fast. Instead 

of doubling the actual clock rate, DDR memory achieves the doubling 

in performance by transferring twice per transfer cycle—once 

at the leading (falling) and once at the trailing (rising) edge of the 

cycle. This is similar to the way RDRAM operates and effectively 

doubles the transfer rate, even though the same overall clock and 

timing signals are used. 

DDR SDRAM is supported by many of the newest server chipsets 

and provides a design alternative to the more radical RDRAM. The 

DDR Consortium—an industry panel consisting of Fujitsu, Ltd.; 

Hitachi, Ltd.; Hyundai Electronics Industries Co.; Mitsubishi 

Electric Corp.; NEC Corp.; Samsung Electronics Co.; Texas 

Instruments, Inc.; and Toshiba Corp.—undertook official standardization 

of DDR. 

2.00 +0.10 

-0.10 

3.99 +0.10 

-0.10 

DDR-SDRAM uses a new DIMM module design with 184 pins. 

Figure 2.11 shows the DDR SDRAM DIMM.

42 


Startup and 

observe POST. 

If errors are 

encountered, 

go to defect 

isolation 

procedures. 

Defect 

Isolation 

Procedures. 

If count does 

not match, go to 

defect isolation 

procedures. 

If problems are 

encountered, go 

to Defect Isolation 

Procedures. 

If POST completes 

with no errors, 

basic functionality 

has been tested. 

Restart system, 

enter Bios (or CMOS) 

setup. Verify that 

memory count is 

equal to installed 

amount. 

While in the BIOS, 

set all cache options 

to disabled, save 

settings and boot to 

a DOS formatted 

(floppy) system disk. 

Use a diagnostics 

program to test 

system base and 

extended memory. 

If no problems are 

encountered, memory 

has tested OK. 

Reboot, enter BIOS 

setup re-enable. 

Figure 2.11 184-pin DDR (Double Data Rate) SDRAM DIMM. 

DDR DIMMs are rated for either PC200 (100MHz x 2) or PC266 

(133MHz x 2) operation and normally run on 2.5 volts. They are 

basically an extension of the PC100 and PC133 DIMMs redesigned 

to support double clocking, where data is sent on each clock transition 

(twice per cycle) rather than once per cycle as is standard with 

SDRAM. 

Parity Versus Non-Parity Memory 

Parity-checked RAM uses units of 8 memory bits plus 1 parity bit, 

for a total of 9 bits. In addition, parity checking uses both the data 

bits and the parity bit to ensure that memory contents are accurate 

with each memory access. 

Virtually all 386-based and older systems, and most 486-based systems, 

require parity-checked memory, which can detect, but not 

correct, memory errors. On the other hand, most Pentium-class

and higher systems don’t require parity-checked RAM, but will 

ignore the parity bit(s) if present. 

Parity-checked memory must be used on systems that require it, 

and should be used on systems that can be configured to use the 

parity bits, especially if the systems support ECC (Error Correction 

Code) operation, which uses the parity bit as a means of correcting a 

faulty memory bit. 

Requirements for ECC Memory Use 

ECC requires the following: 

• Parity-checked memory modules 

• A motherboard chipset that offers ECC support 

• ECC support enabled in the BIOS system configuration 

ECC operation is recommended for servers and other systems that 

are performing mission-critical tasks because ECC operation can 

correct single-bit memory errors. Larger memory errors will cause 

the system to display an error message and halt. 

However, systems using ECC will cost more due to the higher cost 

of parity-checked RAM. Additionally, system performance is slightly 

slower due to the extra time involved in ECC operation. Check 

your motherboard or system documentation to determine whether 

ECC is an option for your system. 

To determine whether a memory module supports parity-checking 

or ECC, use the following tips. 

Using the Divide by 3 Rule to Determine Parity Support 

Count the chips on a SIMM or DIMM. If you can divide the number 

of chips by 3, the module is most likely a parity-checked module. 

However, some memory manufacturers have created memory 

modules with fake parity chips; these are referred to as logic parity 

modules. 

Note 


See Upgrading and Repairing PCs, 12th Edition, Chapter 6, for 

more information about how to detect a logic parity module. 

Using the Divide by 9 Rule to Determine Parity Support 

A similar “divide by 9” rule can also be used to determine parity 

checking if you know the number of memory bits in the module. 

Note in Table 2.16 that the number of bits in parity-checked

44 

modules can be divided by 9, but the number of bits in non-parity 

modules can be divided only by 8. 

Table 2.16 SIMM and DIMM Capacities 

30-Pin SIMM Capacities 

Capacity Parity SIMM Non-Parity SIMM 

256KB 256KB×9 256KB×8 

1MB 1MB×9 1MB×8 

4MB 4MB×9 4MB×8 

16MB 16MB×9 16MB×8 

72-Pin SIMM Capacities 

Capacity Parity SIMM Non-Parity SIMM 

1MB 256KB×36 256KB×32 

2MB 512KB×36 512KB×32 

4MB 1MB×36 1MB×32 

8MB 2MB×36 2MB×32 

16MB 4MB×36 4MB×32 

32MB 8MB×36 8MB×32 

64MB 16MB×36 16MB×32 

128MB 32MB×36 32MB×32 

168-Pin DIMM Capacities 


Capacity Parity DIMM Non-Parity DIMM 

8MB 1MB×72 1MB×64 

16MB 2MB×72 2MB×64 

32MB 4MB×72 4MB×64 

64MB 8MB×72 8MB×64 

128MB 16MB×72 16MB×64 

256MB 32MB×72 32MB×64 

Expanding Memory on a System 

Memory must be added to a system in banks. Simply put, a bank of 

memory is the amount of RAM in bits equal to the data bus width 

of the computer’s CPU (see Table 2.17). Thus, a Pentium’s data bus 

is 64 bits, and a memory module(s) used with a Pentium must have 

a total width of 64 bits for non-parity memory and 72 bits for 

parity-checked or ECC memory.

Table 2.17 Memory Bank Widths on Various Systems 


30-Pin 72-Pin 168-Pin 

Memory Memory SIMMs SIMMs SIMMs 

Data Bank Size Bank Size per per per 

Processor Bus (No Parity) (Parity) Bank Bank Bank 

8088 8-bit 8 bits 9 bits 1 n/a n/a 



386SX, 

SL, SLC 

16-bit 16 bits 18 bits 2 n/a n/a 

386DX 32-bit 32 bits 36 bits 4 1 n/a 

486SLC, 

SLC2 

16-bit 16 bits 18 bits 2 n/a n/a 

486SX, 

DX, DX2, 

DX4, 5x86 

32-bit 32 bits 36 bits 4 1 n/a 

Pentium, 64-bit 64 bits 72 bits 8 1 

K5, K6 

6x86, 

6x86MX, 

MII 

2 1 

Pentium 64-bit 64 bits 72 bits 8 1 

Pro, PII, 

PIII, Celeron, 

Xeon, AMD 

Athlon, 

Duron, Intel 

Itanium 

2 1 

1. Very few motherboards for these processors actually use this type of memory. 

The number of bits for each bank can be made up of single chips, SIMMs, or DIMMs. Modern 

systems don’t use individual chips; instead, they use only SIMMs or DIMMs. If the system has a 

16-bit processor, such as a 386SX, it probably uses 30-pin SIMMs and has two SIMMs per bank. 

All the SIMMs in a single bank must be the same size and type. 

Memory Troubleshooting 

Figure 2.12 provides basic steps that enable you to effectively test 

and troubleshoot your system RAM. First, let’s cover the memory 

testing and troubleshooting procedures. 

After you’ve determined that the system’s memory is defective, you 

need to determine which memory module is at fault. Follow the 

procedure in Figure 2.13 to isolate the module for replacement.

46 


Restart system and 

enter BIOS setup under 

advanced or chipset 

setup, select memory 

timing parameters and 

set all to BIOS defaults. 

Save settings and reboot. 

Retest as shown in 

Figure 6.17. 

Problem 

not solved 

Open your system case. 

Identify the SIMMS/ 

DIMMS/RIMMS. 

Determine the bank 

arrangement. Remove 

and reinstall all of the 

memory modules to 

reseat them. Ensure that 

they are the correct size, 

speed, voltage, and type 

for your system. 

If problem remains with 

all but 1st bank removed, 

problem isolated to 1st 

bank. Replace memory 

modules. 

Problem solved 


If problem does not 

recur after removing/ 

replacing modules, could 

be that contacts need 

cleaned. 

Problem 

not solved 


Figure 2.12 Testing and troubleshooting memory. 

Memory Usage Within the System 

Note which are the 

slowest. 

If problem was solved, 

the improper BIOS 

settings were the culprit. 

If problem is solved with 

all but bank 1 removed, 

the problem could be in 

one of the modules you 

removed. Add 1 at a time, 

and retest. When problem 

appears, replace module. 

If problem still remains 

after all banks are tested, 

replace motherboard. 

The original PC had a total of 1MB of addressable memory, and the 

top 384KB of that was reserved for use by the system. Placing this 

reserved space at the top (between 640KB and 1,024KB instead of at 

the bottom, between 0KB and 640KB) led to what is often called the 

conventional memory barrier. Systems with more than 1MB of RAM 

treat the additional RAM as extended memory, beginning at 1MB. 

Thus, there is a “hole” in memory usage between 640KB and 1MB. 

Some standard add-on cards and motherboard devices use part of 

this memory area for RAM and ROM addresses, leaving the remainder 

of this space free for additional card usage. 

Hardware and Firmware Devices That Use Memory 

Addresses 

The listing of hardware and firmware devices that use memory 

addresses is relatively short when compared to IRQ, DMA, and I/O 

port address usage, but it is no less important. No two devices can 

share a memory address. Table 2.18 shows memory usage in the 

640KB–1MB memory range for standard devices.

Startup and 

observe POST. 

If errors are 

encountered, 

go to defect 

isolation 

procedures. 

Defect 

Isolation 

Procedures 

If count does 

not match, go to 

defect isolation 

procedures. 

If problems are 

encountered, go 

to Defect Isolation 

Procedures. 

Figure 2.13 Follow these steps if you are still encountering memory 

errors after completing the steps in Figure 2.12. 

Table 2.18 Memory Usage in the 640KB–1MB Range 

Device Address Range Notes 

Graphics Mode 

Video RAM 

0A0000–0AFFFF 

Monochrome Text 

Mode Video RAM 

0B0000–0B7FFF 

Color Text Mode 

Video RAM 

0B8000–0BFFFF 

Video ROM for 

VGA, Super VGA 

0C0000–0C7FFF 


If POST completes 

with no errors, 

basic functionality 

has been tested. 

Restart system, 

enter BIOS (or CMOS) 

setup. Verify that 

memory count is 

equal to installed 

amount. 

While in the BIOS, 

set all cache options 

to disabled, save 

settings and boot to 

a DOS formatted 

(floppy) system disk. 

Use a diagnostics 

program to test 

system base and 

extended memory. 

If no problems are 

encountered, memory 

has tested OK. 

Reboot, enter BIOS 

setup re-enable.

48 


Table 2.18 Memory Usage in the 640KB–1MB Range Continued 

Device Address Range Notes 

Unassigned 0C8000–0DFFFF Available for use by BIOS or 

RAM chips on add-on cards 

or by memory managers, 

such as QEMM or EMM386 

Motherboard ROM 0E0000–0EFFFF If not used by BIOS 

BIOS extension extensions, can be 

(IBM PS/2s, most treated as 

Pentium-class additional 

and newer systems) unassigned space 

Motherboard ROM 

BIOS (all systems) 

0F0000–0FFFFF 

If you are using an add-on card that uses a ROM BIOS chip 

onboard to overcome IDE hard drive limitations, overcome Y2K 

date rollover problems, or provide support for bootable SCSI hard 

drives, the BIOS chips on those cards must be placed in the unassigned 

memory range listed earlier. If you have two or more add-on 

cards that use memory address ranges, for best system performance, 

set the cards to use adjacent memory addresses. 

Table 2.19 shows the typical memory uses for some common IDE 

and SCSI interface cards that use ROM BIOS chips. 

Table 2.19 Memory Addresses Used by Various Adapter Cards 

Adapter Type Onboard BIOS Size BIOS Address Range 

Most XT compatible 

controllers 

8KB 0C8000–0C9FFF 

Most AT controllers None Drivers in motherboard BIOS 

Most standard IDE 

hard disk adapters 

None Drivers in motherboard BIOS 

Most enhanced1 IDE hard disk adapters 

16KB 0C8000–0CBFFF 

Some SCSI host adapters 16KB 0C8000–0CBFFF 

Some SCSI host adapters 16KB 0DC000–0DFFFF 

1. This type of adapter supplements the motherboard’s IDE interface by supporting drives beyond 

528MB (decimal) or 504MB (binary), or beyond 8.4GB (decimal) in size. Some of these 

adapters can also provide Y2K-date rollover support. Cards that combine both functions might 

use a larger (in KB) BIOS chip. 

Some older network cards also used memory addresses for RAM 

buffers or for ROM BIOS chips that permit diskless workstations to 

use a network copy of the operating system for booting. Network 

cards that use memory addresses are seldom used today.


Using Memory Addresses Beyond 1MB (0FFFFF) 

Some older Super VGA cards, notably those from ATI, could also be 

set to use a 1MB extended memory address starting at 15MB for 

moving video data. This so-called memory aperture technique made 

the video cards using it faster, but could not be used on systems 

with 16MB of RAM or above. If you use a video card that uses a 

fixed memory aperture at 15MB on a system with less than 16MB 

of RAM, disable the memory aperture feature before you upgrade 

the RAM beyond 16MB. Some current PCI and AGP video cards 

also use memory apertures, but at addresses that do not interfere 

with today’s larger amounts of system RAM. 

Determining Memory Address Ranges in Use 

On a system with Windows 9x, Windows 2000, or Windows Me, 

use the Device Manager’s System Properties sheet to see overall 

memory address usage (see Figure 2.14). 

Use add-on card documentation or a memory viewer,such as those 

included with AMIDiag, CheckIt, or Microsoft’s MSD.EXE, to see 

memory usage on systems running Windows 3.1 or MS-DOS. 

Figure 2.14 A system’s upper memory usage as displayed by the 

Windows 9x Device Manager. Addresses between 000CCFFFF and 000DFFFF 

in upper memory are available for add-on cards. The ATI video card onboard 

also uses memory addresses above 1MB for a high-speed memory aperture. 

Note 

To learn more about memory modules, see Chapter 6 of 

Upgrading and Repairing PCs, 12th Edition, published by Que.

50 

Other Add-On Card Configuration 

Issues 

When a card is installed into an expansion slot or a PCMCIA/PC 

card device is installed into a PC card slot, the card must use at 

least one of four hardware resources to be accessible to the system. 

All add-on cards must use at least an I/O port address range or 

ranges; most cards use an IRQ (interrupt request line); fewer cards 

use DMA (Direct Memory Access); and memory addresses are used 

least of all. Many cards use two or more of these hardware 

resources. 

Note 


For more information, see the section “Hardware and Firmware 

Devices That Use Memory Addresses,” earlier in this chapter. 

If an add-on card is set to use the same hardware resource as an 

existing card, it will not work unless that resource is designed to be 

shared between cards. Although the capability to share IRQs has 

existed (at least in theory) since the Micro Channel Architecture of 

the late 1980s, even today the best rule of thumb for adding cards 

is “each card has its own settings.” 

Plug-and-Play (PnP) configuration—introduced with Windows 95 

and also present with Windows 98, Windows Me, and Windows 

2000—is designed to minimize much of the grief of adding cards, 

but this technology has been in a state of flux since it was introduced. 

To help you add cards, the following tables of standard settings 

also list software and hardware tools that can help you find 

the settings already in use before you install your next card. 

IRQs 

Interrupt request channels (IRQs), or hardware interrupts, are used by 

various hardware devices to signal the motherboard that a request 

must be fulfilled. Most add-on cards use IRQs, and because systems 

today have the same number of IRQs available with the first IBM 

PC/AT systems built in 1984, IRQs frequently cause trouble in addon 

card installations. 

Table 2.20 shows IRQ assignments for 16-bit ISA and 32-bit 

VL-Bus/PCI expansion slots, listed by priority. Technically speaking, 

PCI interrupts can be shared, but in practice, many older Pentium 

systems must use a unique IRQ value for each PCI card, as with ISA 

and VL-Bus cards.

Table 2.20 16/32-Bit ISA/VL-Bus/PCI Default Interrupt 

Assignments 


Standard Recommended 

IRQ Function Bus Slot Card Type Use 

0 System timer No — — 

1 Keyboard 

controller 

No — — 

21 Second IRQ 

controller 

cascade 

No — — 

8 Real-time clock No — — 

9 Available Yes 8-/16-bit Network 

(appears as Interface 

IRQ 2) Card 

10 Available Yes 16-bit USB 

11 Available Yes 16-bit SCSI host adapter 

12 Motherboard Yes 16-bit Motherboard 

mouse port 

available 

mouse port 

13 Math 

coprocessor 

No — — 

14 Primary IDE Yes 16-bit Primary IDE (hard 

disks) 

15 Secondary IDE/ Yes 16-bit Secondary IDE 

available (CD-ROM/ tape) 

34 Serial Port 2 Yes 8-/16-bit COM 2:/internal 

(COM 2:) modem 

43 Serial Port 1 

(COM 1:) 

Yes 8-/16-bit COM 1: 

52 Sound/Parallel 

Port 2 (LPT2:) 

Yes 8-/16-bit Sound card 

6 Floppy disk Yes 8-/16-bit Floppy 

controller controller 

7 Parallel Port 

1 (LPT1:) 

Yes 8-/16-bit LPT1: 

1. The original IBM PC/XT and compatible systems with 8-bit ISA slots did not assign any standard 

device to IRQ 2. When the 16-bit ISA slot was introduced, along with a second range of 

IRQs (8–15), this permitted the “cascading” of these interrupts via IRQ 2. Older cards that 

have IRQ 2 as a setting actually use IRQ 9 instead on 286-based and higher systems. 

2. On original XT-class systems with 8-bit ISA slots, IRQ 5 was assigned to the hard disk controller 

card. Even though IRQ 5’s “official” assignment is to handle LPT2 on systems with 

16-bit ISA slots, only EPP and ECP (IEEE-1284) parallel port modes actually use an IRQ. This 

permits the use of IRQ 5 for sound cards in most systems without interfering with the use of 

LPT2. 

3. Systems with COM 3 default to “sharing” COM 1’s IRQ 4. This will cause system lockups in 

Windows if a serial mouse is used on COM 1 with a modem on COM 3. Use the modem, and 

the IRQ conflict crashes the system. To avoid problems, set the device using COM 3 to a different 

IRQ, or disable COM 2 and use COM 2 for the modem.

52 


4. Systems with COM 4 default to “sharing” COM 2’s IRQ 3. This will cause system lockups in 

Windows if a serial mouse is used on COM 2 with a modem on COM 4. Use the modem, and 

the IRQ conflict crashes the system. To avoid problems, set the device using COM 4 to a different 

IRQ, or disable COM 2 and use COM 2 for the modem. 

DMA 

Direct Memory Access permits high-speed data transfer between 

I/O devices and memory without CPU management. This method 

of data transfer boosts performance for devices that use it, but 

because there is no CPU management, the possibility of data corruption 

is higher than for non-DMA transfers. Although DMA 

channels can theoretically be “shared” between devices that are not 

in use at the same time, this is not a recommended practice. 

PCI cards don’t use these DMA channels (with the exception of 

sound cards, which are emulating the ISA-based Sound Blaster 

or compatibles—the major users of DMA channels today). See 

Table 2.21. 

Table 2.21 16/32-Bit ISA/PCI Default DMA-Channel Assignments 

Standard Bus Card Recommended 

DMA Function Slot Type Transfer Use 

0 Available Yes 16-bit 8-bit Integrated sound 

1 Available Yes 8-/16-bit 8-bit 8-bit sound 

2 Floppy disk Yes 8-/16-bit 8-bit Floppy 

controller controller 

3 Available Yes 8-/16-bit 8-bit LPT1: in ECP mode 

4 1st DMA 

controller 

cascade 

No — 16-bit — 

5 Available Yes 16-bit 16-bit 16-bit sound 

6 Available Yes 16-bit 16-bit ISA SCSI adapter 

7 Available Yes 16-bit 16-bit Available 

Note that PCI adapters don’t use these ISA DMA channels; these are only for ISA cards. 

On PC/XT systems with only 8-bit ISA slots, only DMA channels 1–3 are available. DMA channel 

2 was used for the floppy controller, as it is today, but channels 1 and 3 were not assigned to 

standard devices. 

Determining Actual IRQ and DMA Usage 

Although these tables provide the “official” guidelines for IRQ and 

DMA usage, these settings might not be true for all systems at all 

times. 

Add-on network, sound, serial, parallel, and SCSI cards can often be 

moved to different IRQ and DMA channels to work around conflicts. 

Non-standard settings can be done manually with some cards 

and is a virtual certainty with PnP cards used with Windows 9x and 

Windows 2000. Well-designed PnP cards already installed in a


system are designed to automatically move to non-conflicting settings 

when less-flexible PnP cards are inserted. Late-model 

Pentium-class systems using Windows 95 OSR 2.x, Windows 98, 

Windows 2000, or Windows Me can also use an IRQ holder for PCI 

steering feature that allows multiple PCI devices to use a single 

IRQ, if the BIOS is designed to support it. 

To view the current IRQ and DMA settings for systems using 

Windows 9x, use the Device Manager (a tab on the System 

Properties sheet). View the properties for the “Computer” icon at 

the top of the device list and you can choose from IRQ, DMA, I/O 

port, and Memory address information (see Figure 2.15). 

Figure 2.15 The Windows 9x Device Manager and Computer Properties 

sheet shows IRQs in use; available IRQs are not listed. The IRQ steering feature 

enables IRQ 5 to be shared between two different PCI-based cards without 

conflicts. 

For other operating systems, I recommend an interface card with 

signal lights for IRQ and DMA usage. The Discovery Card, developed 

by John Rourke, pioneered this diagnostic category, and many 

vendors offer cards with this feature. Some vendors combine 

IRQ/DMA detection with POST code detection or active system 

testing. 

To use an IRQ/DMA card, turn off the system, insert the card into 

an open slot, and turn on the system. As devices that use an IRQ or 

a DMA are activated, the corresponding signal light on the card is 

displayed. Most cards have a reset switch, which enables the card 

lights to be cleared, allowing you to test for possible conflicts. When 

combined with information from a system configuration template, 

this helps provide accurate IRQ and DMA usage information.

54 


I/O Port Addresses 

Your computer’s I/O ports enable communications between devices 

and software in your system. They are equivalent to two-way radio 

channels. If you want to talk to your serial port, you need to know 

which I/O port (radio channel) it is listening on. Similarly, if you 

want to receive data from the serial port, you need to listen on the 

same channel on which it is transmitting. 

One confusing issue is that I/O ports are designated by hexadecimal 

addresses similar to memory addresses. They are not memory; 

they are ports. 

Motherboard and chipset devices are normally set to use I/O port 

addresses from 0h to FFh, and all other devices use from 100h to 

FFFFh. Table 2.22 shows motherboard and chipset-based I/O port 

usage. 

Table 2.22 Motherboard and Chipset-Based Device Port Addresses 

Address (Hex) Size Description 

0000–000F 16 bytes Chipset - 8237 DMA 1 

0020–0021 2 bytes Chipset - 8259 interrupt controller 1 

002E–002F 2 bytes Super I/O controller configuration registers 

0040–0043 4 bytes Chipset - Counter/Timer 1 

0048–004B 4 bytes Chipset - Counter/Timer 2 

0060 1 byte Keyboard/Mouse controller byte - reset IRQ 

0061 1 byte Chipset - NMI, speaker control 

0064 1 byte Keyboard/mouse controller, CMD/STAT byte 

0070, bit 7 1 bit Chipset - Enable NMI 

0070, bits 6:0 7 bits MC146818 - Real-time clock, address 

0071 1 byte MC146818 - Real-time clock, data 

0078 1 byte Reserved - Board configuration 

0079 1 byte Reserved - Board configuration 

0080–008F 16 bytes Chipset - DMA page registers 

00A0–00A1 2 bytes Chipset - 8259 interrupt controller 2 

00B2 1 byte APM control port 

00B3 1 byte APM status port 

00C0–00DE 31 bytes Chipset - 8237 DMA 2 

00F0 1 byte Math coprocessor reset numeric error 

To find out exactly which port addresses are being used on your 

motherboard, consult the board documentation or look up the settings 

in the Windows Device Manager.


Bus-based devices (I/O devices found on the motherboard or on 

add-on cards) normally use the addresses from 100h on up. Table 

2.23 lists the commonly used bus-based device addresses and some 

common adapter cards and their settings. 

Table 2.23 Bus-Based Device Port Addresses 


0130–0133 4 bytes Adaptec SCSI adapter (alternate 

0134–0137 4 bytes Adaptec SCSI adapter (alternate) 

0168–016F 8 bytes Fourth IDE interface 

0170–0177 8 bytes Secondary IDE interface 

01E8–01EF 8 bytes Third IDE interface 

01F0–01F7 8 bytes Primary IDE/AT (16-bit) hard disk controller 

0200–0207 8 bytes Gameport or joystick adapter 

0210–0217 8 bytes IBM XT expansion chassis 

0220–0233 20 bytes Creative Labs Sound Blaster 16 audio (default) 



0238–023B 4 bytes MS bus mouse (alternate) 

023C–023F 4 bytes MS bus mouse (default) 

0240–024F 16 bytes SMC Ethernet adapter (default) 

0240–0253 20 bytes Creative Labs Sound Blaster 16 audio (alternate) 

0258–025F 8 bytes Intel above board 

0260–026F 16 bytes SMC Ethernet adapter (alternate) 


0270–0273 4 bytes Plug-and-Play I/O read ports 

0278–027F 8 bytes Parallel Port 2 (LPT2) 



02A0–02AF 16 bytes SMC Ethernet adapter (alternate) 

02C0–02CF 16 bytes SMC Ethernet adapter (alternate) 

02E0–02EF 16 bytes SMC Ethernet adapter (alternate 

02E8–02EF 8 bytes Serial Port 4 (COM 4) 

02EC–02EF 4 bytes Video, 8514, or ATI standard port 

02F8–02FF 8 bytes Serial Port 2 (COM 2) 

0300–0301 2 bytes MPU-401 MIDI port (secondary) 


0320–0323 4 bytes XT (8-bit) hard disk controller 


0330–0331 2 bytes MPU-401 MIDI port (default) 

0330–0333 4 bytes Adaptec SCSI adapter (default) 

0334–0337 4 bytes Adaptec SCSI adapter (alternate)

56 


Table 2.23 Bus-Based Device Port Addresses Continued 




0366 1 byte Fourth IDE command port 

0367, bits 6:0 7 bits Fourth IDE status port 

0370–0375 6 bytes Secondary floppy controller 

0376 1 byte Secondary IDE command port 

0377, bit 7 1 bit Secondary floppy controller disk change 

0377, bits 6:0 7 bits Secondary IDE status port 

0378–037F 8 bytes Parallel Port 1 (LPT1) 


0388–038B 4 bytes Audio - FM synthesizer 

03B0–03BB 12 bytes Video, Mono/EGA/VGA standard ports 

03BC–03BF 4 bytes Parallel Port 1 (LPT1) in some systems 

03BC–03BF 4 bytes Parallel Port 3 (LPT3) 

03C0–03CF 16 bytes Video, EGA/VGA standard ports 

03D0–03DF 16 bytes Video, CGA/EGA/VGA standard ports 

03E6 1 byte Third IDE command port 

03E7, bits 6:0 7 bits Third IDE status port 

03E8–03EF 8 bytes Serial Port 3 (COM 3) 

03F0–03F5 6 bytes Primary floppy controller 

03F6 1 byte Primary IDE command port 

03F7, bit 7 1 bit Primary floppy controller disk change 

03F7, bits 6:0 7 bits Primary IDE status port 

03F8–03FF 8 bytes Serial Port 1 (COM 1) 

04D0–04D1 2 bytes Edge/level triggered PCI interrupt controller 

0530–0537 8 bytes Windows sound system (default) 

0604–060B 8 bytes Windows sound system (alternate) 

0678–067F 8 bytes LPT2 in ECP mode 

0778–077F 8 bytes LPT1 in ECP mode 

0A20–0A23 4 bytes IBM Token-Ring adapter (default) 

0A24–0A27 4 bytes IBM Token-Ring adapter (alternate) 

0CF8–0CFB 4 bytes PCI configuration address registers 

0CF9 1 byte Turbo and reset control register 

0CFC–0CFF 4 bytes PCI configuration data registers 

FF00–FF07 8 bytes IDE bus master registers 

FF80–FF9F 32 bytes Universal Serial Bus (USB) 

FFA0–FFA7 8 bytes Primary bus master IDE registers 

FFA8–FFAF 8 bytes Secondary bus master IDE registers


Determining Actual I/O Address Ranges in Use 

To find out exactly what your devices are using, consult the documentation 

for the device or look up the device in the Windows 9x 

Device Manager (see Figure 2.16). Note that some device documentation 

might list only the starting I/O address and not the full 

range of addresses used. 

Virtually all devices on your system buses use I/O port addresses. 

Most of these are fairly standardized, meaning you won’t often 

have conflicts or problems with these settings. 

Figure 2.16 The Windows 9x Device Manager lists the starting and ending 

I/O port addresses for both motherboard-based and add-on card devices. 

Troubleshooting Add-on Card Resource Conflicts 

The resources in a system are limited. Unfortunately, the demands 

on those resources seem to be unlimited. As you add more and 

more adapter cards to your system, you will find that the potential 

for resource conflicts increases. 

Symptoms of a Potential Resource Conflict 

• A device transfers data inaccurately. 

• Your system frequently locks up. 

• Your sound card doesn’t sound quite right. 

• Your mouse doesn’t work. 

• Garbage appears on your video screen for no apparent reason. 

• Your printer prints gibberish.

58 


• You cannot format a floppy disk. 

• The PC starts in Safe mode (Windows 9x/2000/Me). 

Spotting Resource Conflicts with Windows 9x/2000/Me 

Windows 9x/Me/2000 also show conflicts by highlighting a device 

in yellow or red in the Device Manager representation. By using the 

Windows Device Manager, you can usually spot the conflicts 

quickly (see Figure 2.17). 

Keep in mind that many computer viruses can also cause symptoms 

similar to hardware resource conflicts. Scan your system for 

viruses before you start working on it. 

Recording System Settings 

Use a System Configuration Template to record system settings. 

This sheet is resource-oriented, not device-oriented, to make finding 

conflicts easier. You can make a printout of the System 

Summary from the Windows 9x/Me/2000 Device Manager to get a 

lot of this information. For other operating systems, use the methods 

listed earlier. 

The first system resource map is provided as a model for your use; 

it lists fixed resources on a modern PC. Add the other resources 

used on your PC. Note that many high-performance PCI or AGP 

video cards do use an IRQ, although some motherboard chipsets 

have a provision for disabling the IRQ usage. 

Figure 2.17 The yellow circle next to the Adaptec 154x SCSI card indicates 

a conflict; view the card resources (right window) to see the conflicting device.

System Resource Map 


PC Make and Model: _________________________ 

Serial Number: _________________________ 

Date: _________________________ 

Interrupts (IRQs): I/O Port Addresses: 

0 - Timer Circuits ______________ 040-04B ______________ 

1 - Keyboard/Mouse Controller ____ 060 & 064 ____________ 

2 - 2nd 8259 IRQ Controller ______ 0A0-0A1______________ 

8 - Real-time Clock/CMOS RAM ____ 070-071______________ 

9 - ________________________ ____________________ 

10 - ________________________ ____________________ 

11 - ________________________ ____________________ 

12 - ________________________ ____________________ 

1 3 - Math Coprocessor ___________ 0F0 _________________ 

14 - ________________________ ____________________ 

15 - ________________________ ____________________ 

3 - ________________________ ____________________ 

4 - ________________________ ____________________ 

5 - ________________________ ____________________ 

6 - ________________________ ____________________ 

7 - ________________________ ____________________ 

Devices not using Interrupts: I/O Port Addresses: 

Mono/EGA/VGA Standard Ports_____ 3B0-3BB______________ 

EGA/VGA Standard Ports _________ 3C0-3CF ______________ 

CGA/EGA/VGA Standard Ports _____ 3D0-3DF______________ 

____________________________ ____________________ 

____________________________ ____________________ 

____________________________ ____________________ 

____________________________ ____________________ 

____________________________ ____________________ 

____________________________ 

DMA Channels: 

____________________ 

0 - ________________________ 

1 - ________________________ 

2 - ________________________ 

3 - ________________________ 

4 - DMA Channel 0-3 Cascade _____ 

5 - ________________________ 

6 - ________________________ 

7 - ________________________

60 


Here’s an example of how to fill out the worksheet: 

System Resource Map 

PC Make and Model: Intel SE440BX-2 ________ 

Serial Number: 100000______________ 

Date: 06/09/99 ____________ 

Interrupts (IRQs): I/O Port Addresses: 

0 - Timer Circuits ______________ 040-04B ______________ 

1 - Keyboard/Mouse Controller ____ 060 & 064 ___________ 

2 - 2nd 8259 IRQ Controller ______ 0A0-0A1 ____________ 

8 - Real-time Clock/CMOS RAM ____ 070-071 ____________ 

9 - SMC EtherEZ Ethernet card ____ 340-35F_____________ 

10 - ________________________ ___________________ 

1 1 - Adaptec 1542CF SCSI Adapter 334-3371 (scanner) 

____________ 

1 2 - Motherboard Mouse Port ______ 060 & 064 ___________ 

1 3 - Math Coprocessor ___________ 0F0 ________________ 

1 4 - Primary IDE (hard disk 1 and 2) _ 1F0-1F7, 3F6 _________ 

1 5 - Secondary IDE (CD-ROM/tape) _ _ 170-177, 376 ________ 

3 - Serial Port 2 (Modem) ________ 3F8-3FF _____________ 

4 - Serial Port 1 (COM1) _________ 2F8-2FF _____________ 

5 - Sound Blaster 16 Audio_______ 220-233 ____________ 

6 - Floppy Controller ___________ 3F0-3F5 _____________ 

7 - Parallel Port 1 (Printer) _______ 378-37F_____________ 

Devices not using interrupts: I/O Port Addresses: 

Mono/EGA/VGA Standard Ports ______ 3B0-3BB ___________ 

EGA/VGA Standard Ports___________ 3C0-3CF ___________ 

CGA/EGA/VGA Standard Ports_______ 3D0-3DF ___________ 

ATI Mach 64 video card additional ports _ 102,1CE-1CF,2EC-2EF _ _ 

Sound Blaster 16 MIDI port _________ 330-331 ___________ 

Sound Blaster 16 Game port (joystick)_ 200-207 ___________ 

Sound Blaster 16 FM synthesizer (music) 

388-38B ______________________ 

__________________ 

_____________________________ 

DMA Channels: 

__________________ 

0 -____________________________ 

1 - Sound Blaster 16 (8-bit DMA) ______ 

2 - Floppy Controller _______________ 

3 - Parallel Port 1 (in ECP mode)_______ 

4 - DMA Channel 0-3 Cascade _________ 

5 - Sound Blaster 16 (16-bit DMA) _____ 

6 - Adaptec 1542CF SCSI adapter 1 _____ 

7 - ____________________________


1. Represents a resource setting that had to be changed to resolve a conflict. 

After you’ve completed your system resource map by recording the 

current settings for hardware, you’re ready to solve conflicts. 

Note 

Resource use can change whenever PnP or non-PnP hardware is 

installed or removed, so you should update this chart whenever 

you add or remove internal hardware. 

Resolving Conflicts by Card and Operating System Type 

Table 2.24 Guide to Resolving Conflicts 

Operating System Card Type Notes 

Windows 9x/ PnP Use Device Manager to change card settings 

2000/Me if possible; remove and reinstall card to redetect 

card and use new settings if card can’t be 

set manually; if new card can’t be detected 

when installed, remove other PnP cards and 

install new card first. 

Non-PnP Use Device Manager to see conflicting 

devices; manually configure cards to nonconflicting 

settings by changing jumpers, DIP 

switches, or rerunning configuration programs. 

Other operating Any When did the conflict first become apparent? 

systems If the conflict occurred after you installed a 

new adapter card, that new card probably is 

causing the conflict. If the conflict occurred 

after you started using new software, chances 

are good that the software uses a device that 

is taxing your system’s resources in a new 

way. 

Are two similar devices in your system not working? 

For example, if your modem, integrated 

serial ports, or mouse devices that use a COM 

port do not work, chances are good that 

these devices are conflicting with each other. 

Have other people had the same problem? And if 

so, how did they resolve it? Public forums such 

as those on CompuServe, Internet newsgroups, 

and America Online are great places 

to find other users who might be able to help 

you solve the conflict. Also check vendor 

forums for help. 

After you research these questions, make one 

(one!) change to your system configuration, 

reboot the computer and see whether the 

problem is now resolved. Repeat with a different 

setting until the problem is solved. 

Test all components to make sure that “fixing” 

one component didn’t cause a conflict with

62 


another. 

Expansion Slots 

If you want to add network, SCSI, modem, or sound capabilities to 

an existing system or upgrade your video card, you need to understand 

expansion slots. Expansion slots act as an extension of the 

system bus and permit you to connect cards with different features 

to your system. 

ISA 

ISA (Industry Standard Architecture) expansion slots are the oldest 

expansion slot design found in current PCs. 8-bit versions go all 

the way back to the original IBM PC of 1981. While 8-bit–only ISA 

slots have faded away, 16-bit ISA slots (introduced with the IBM 

PC/AT in 1984) are fully pin-compatible with 8-bit ISA cards. See 

Figures 2.18 and 2.19. 

Figure 2.19 shows the orientation and relation of 8-bit and 16-bit 

ISA bus slots. 

EISA—A 32-bit Version of ISA 

The EISA (Enhanced ISA) bus was developed from the ISA architecture 

to provide 32-bit data transfers. The EISA expansion slot (introduced 

in 1988) is a deeper version of ISA, providing a second, offset 

row of connectors that allows EISA slots to support ISA cards. 

Figure 2.20 shows the locations of the pins. 

Because of its high cost and limited performance boost over ISA, 

EISA bus systems have primarily been used for network file servers 

using 386, 486, and occasionally Pentium-class CPUs. 

EISA was introduced as a response to IBM’s MicroChannel architecture, 

which was used primarily on more-advanced models of IBM’s 

PS/2 line from 1987 until the early 1990s. It is now obsolete. 

VL-Bus—A Faster 32-Bit Version of ISA 

Introduced in 1992, the VL-Bus (VESA Local-Bus) was an improved 

32-bit version of ISA designed originally to provide faster video

Signal 

Ground 

RESET DRV 

+5 Vdc 

IRQ 9 

-5 Vdc 

DRQ 2 

-12 Vdc 

-0 WAIT 

+12 Vdc 

Ground 

-SMEMW 

-SMEMR 

-IOW 

-IOR 

-DACK 3 

DRQ 3 

-DACK 1 

DRQ 1 

-Refresh 

CLK(8.33MHz) 

IRQ 7 

IRQ 6 

IRQ 5 

IRQ 4 

IRQ 3 

-DACK 2 

T/C 

BALE 

+5 Vdc 

OSC(14.3MHz) 

Ground 

-MEM CS16 

-I/O CS16 

IRQ 10 

IRQ 11 

IRQ 12 

IRQ 15 

IRQ 14 

-DACK 0 

DRQ 0 

-DACK 5 

DRQ5 

-DACK 6 

DRQ 6 

-DACK 7 

DRQ 7 

+5 Vdc 

-Master 

Ground 

Pin Pin Signal 

B1 

B2 

B3 

B4 

B5 

B6 

B7 

B8 

B9 

B10 

B11 

B12 

B13 

B14 

B15 

B16 

B17 

B18 

B19 

B20 

B21 

B22 

B23 

B24 

B25 

B26 

B27 

B28 

B29 

B30 

B31 

D1 

D2 

D3 

D4 

D5 

D6 

D7 

D8 

D9 

D10 

D11 

D12 

D13 

D14 

D15 

D16 

D17 

D18 

A1 

A2 

A3 

A4 

A5 

A6 

A7 

A8 

A9 

A10 

A11 

A12 

A13 

A14 

A15 

A16 

A17 

A18 

A19 

A20 

A21 

A22 

A23 

A24 

A25 

A26 

A27 

A28 

A29 

A30 

A31 

C1 

C2 

C3 

C4 

C5 

C6 

C7 

C8 

C9 

C10 

C11 

C12 

C13 

C14 

C15 

C16 

C17 

C18 


-I/O CH CHK 

Data Bit 7 

Data Bit 6 

Data Bit 5 

Data Bit 4 

Data Bit 3 

Data Bit 2 

Data Bit 1 

Data Bit 0 

-I/O CH RDY 

AEN 

Address 19 

Address 18 

Address 17 

Address 16 

Address 15 

Address 14 

Address 13 

Address 12 

Address 11 

Address 10 

Address 9 

Address 8 

Address 7 

Address 6 

Address 5 

Address 4 

Address 3 

Address 2 

Address 1 

Address 0 

-SBHE 

Latch Address 23 







-MEMR 

-MEMW 

Data Bit 8 

Data Bit 9 

Data Bit 10 

Data Bit 11 

Data Bit 12 

Data Bit 13 

Data Bit 14 

Data Bit 15 

card performance on 486-based systems. This slot design, like EISA,

64 


8/16-bit ISA Bus Pinouts. 

8-bit PC/XT Connector: 16-bit AT Connector: 

Signal Pin Numbers Signal 

GROUND B1 A1 -I/O CHK 

RESET DRV B2 A2 DATA 7 

+5 Vdc B3 A3 DATA 6 

IRQ 2 B4 A4 DATA 5 

-5 Vdc B5 A5 DATA 4 

DRQ 2 B6 A6 DATA 3 


-CARD SLCT B8 A8 DATA 1 


GROUND B10 A10 -I/O RDY 

-SMEMW B11 A11 AEN 

-SMEMR B12 A12 ADDR 19 

-IOW B13 A13 ADDR 18 

-IOR B14 A14 ADDR 17 

-DACK 3 B15 A15 ADDR 16 

DRQ 3 B16 A16 ADDR 15 



-REFRESH B19 A19 ADDR 12 

CLK (4.77MHz) B20 A20 ADDR 11 

IRQ 7 B21 A21 ADDR 10 






T/C B27 A27 ADDR 4 

BALE B28 A28 ADDR 3 

+5 Vdc B29 A29 ADDR 2 

OSC (14.3MHz) B30 A30 ADDR 1 

GROUND B31 A31 ADDR 0 

Signal Pin Numbers Signal 

GROUND B1 A1 -I/O CHK 

RESET DRV B2 A2 DATA 7 


IRQ 9 B4 A4 DATA 5 


DRQ 2 B6 A6 DATA 3 


-OWS B8 A8 DATA 1 


GROUND B10 A10 -I/O RDY 

-SMEMW B11 A11 AEN 

-SMEMR B12 A12 ADDR 19 

-IOW B13 A13 ADDR 18 

-IOR B14 A14 ADDR 17 





-REFRESH B19 A19 ADDR 12 

CLK (8.33MHz) B20 A20 ADDR 11 







T/C B27 A27 ADDR 4 

BALE B28 A28 ADDR 3 

+5 Vdc B29 A29 ADDR 2 

OSC (14.3MHz) B30 A30 ADDR 1 

GROUND B31 A31 ADDR 0 

-MEM CS16 D1 C1 -SBHE 

-I/O CS16 D2 C2 LADDR 23 

IRQ 10 D3 C3 LADDR 22 





-DACK 0 D8 C8 LADDR 17 

DRQ 0 D9 C9 -MEMR 

-DACK 5 D10 C10 -MEMW 

DRQ 5 D11 C11 DATA 8 

-DACK 6 D12 C12 DATA 9 


-DACK 7 D14 C14 DATA 11 


+5 Vdc D16 C16 DATA 13 

-MASTER D17 C17 DATA 14 

GROUND D18 C18 DATA 15 

is now obsolete. While most VL-Bus slots were added to an ISA

B F E A 

1 

2 

3 

4 

5 

6 

1 

2 

3 

4 

5 


slot, the VL-Bus connector could also be added to an EISA slot. 

Thus, any VL-Bus slot is also an ISA or an ISA/EISA slot (see Figure 

2.21). 

1 

2 

3 

4 

5 

1 

2 

3 

4 

5 

6 

7 

7 

8 

9 

7 

8 

9 

7 

8 

9 

8 

9 

10 

10 10 

10 

11 

12 

11 

12 

11 

12 

11 

12 

13 

13 13 

13 

14 

14 14 

14 

15 

16 

15 15 

15 

16 

17 

18 

17 

18 

17 

18 

17 

18 

19 

19 19 

19 

20 

20 20 

20 

21 

22 

21 

22 

21 

22 

21 

22 

23 

23 23 

23 

24 

24 24 

24 

25 

25 

26 

27 

28 

29 

26 

27 

28 

29 

26 

27 

28 

29 

26 

27 

28 

29 

30 

30 30 

30 

31 

31 31 

31 

1 1 

2 

1 

2 

1 

3 

2 

3 

2 

4 

3 

4 

3 

5 

4 

5 

4 

5 5 

7 

6 

7 

6 

8 

7 

8 

7 

9 

8 

9 

8 

10 

9 

10 

9 

11 

10 

11 

10 

12 

11 

12 

11 

13 

12 

13 

12 

14 

13 

14 

13 

14 14 

16 

15 

16 

15 

17 

16 

17 

16 

18 

17 

18 

17 

19 

18 

19 

18 

H D G 

C 

Rear of computer

66 


ISA 

ISA 

Figure 2.18 Pinouts for the 16-bit ISA bus. 

Figure 2.19 The 8-bit and 16-bit ISA bus connectors. 

VL-Bus Extension 

Figure 2.20 The card connector for the EISA bus. The inner connectors 

were used for the EISA cards, whereas the outer connectors supported 8-bit 

and 16-bit ISA cards. 

Figure 2.21 An example of a VL-Bus slot in an ISA system. 

PCI 

Intel developed PCI (Peripheral Component Interconnect) in 1992 

to eventually replace ISA and its variations. Most PCI slots provide 

32-bit transfers, with a 64-bit version of PCI being used in many 

late-model file servers. 

While a number of new “legacy-free” systems offer only PCI slots, 

most systems you will encounter will also have one or more ISA 

slots, as in Figure 2.21. 

AGP 

The latest expansion slot design is AGP (Accelerated Graphics Port), 

introduced in 1996 to provide faster video performance in a dedicated 

slot. AGP doesn’t replace PCI for general purposes, but AGP 

video cards offer much faster performance than similar PCI cards, 

and can also “borrow” from main memory for 3D texturing. Most 

typical Pentium II/III, Celeron, Athlon, Duron, or Super Socket 7 

systems include a single AGP slot as well as a mixture of PCI and 

ISA slots (see Figure 2.22). 

Note


While AGP video is standard on all desktop systems today, it is 

often implemented on very low-cost systems by means of 

onboard video rather than an AGP slot. 

Table 2.25 provides a visual quick reference for expansion slots 

found in modern PCs. 

Figure 2.22 The AGP slot is located at the first (inside) slot position on 

motherboards with an AGP slot. Note the lack of space between the last PCI 

slot and the first ISA slot. This is called a combo or shared slot; only one of 

the slots can actually be used. 

Table 2.25 Expansion Slot Quick-Reference Table 

Slot Type Bus Speed Bus Width Best Use 

ISA 8.33MHz 8-bit or 16-bit Modems, serial, parallel 

ports; will be phased out in 

early twenty-first century 

EISA 8.33MHz 32-bit with Obsolete for most uses; 

EISA cards; works well with servercompatible 

with ISA cards 

optimized NIC cards 

MCA 10MHz 16-bit or 32-bit Introduced with IBM 

MicroChannel PS/2s in 1987; 

obsolete 

VL-Bus 25–33MHz 32-bit; slot also Obsolete; was popular for 

typical; can can be used video cards and IDE hard 

be run up 

to 40MHz 

on some 

systems 

as ISA disk interfaces 

PCI 25–33MHz Most are 32-bit; Video, SCSI, sound, 

(depends some 64-bit modems; replaced ISA 

on speed implementations as general-purpose bus

Chapter 3 

3 

BIOS Configurations 

and Upgrades 

What the BIOS Is and What It Does 

The BIOS (basic input/output system) chip on the computer’s 

motherboard is designed to provide the essential interfacing 

between hardware (such as drives, the clock, the CPU, the chipset, 

and video) and software (the operating system). While video, some 

SCSI, and a few IDE add-on cards might also have BIOS chips that 

help manage those devices, whenever I refer to the computer’s BIOS 

chip, I mean the one on the motherboard. The BIOS chip is often 

referred to as the ROM BIOS, because in its traditional form it was a 

read-only memory chip with contents that could not be changed. 

Later versions could be reprogrammed with an EEPROM programmer, 

and beginning in the early 1990s, BIOSes using flash memory 

(Flash BIOS) began to appear. Flash BIOSes can be reprogrammed 

through software, and virtually all BIOSes on Pentium-class 

machines and beyond are flash upgradable. 

Regardless of its form, the BIOS chip on the motherboard is also 

known as the system BIOS. 

When a BIOS Update Is Necessary 

The following list shows the primary benefits of a ROM BIOS 

upgrade: 

• Adds LS-120 (120MB) floppy drive support (also known as a 

SuperDrive) 

• Adds support for hard drives greater than 8GB 

• Adds support for Ultra-DMA/33 or faster IDE hard drives 

• Adds support for bootable ATAPI CD-ROM drives 

• Adds or improves Plug-and-Play support and compatibility 

• Corrects year-2000 and leap-year bugs 

• Corrects known bugs or compatibility problems with certain 

hardware and software 

• Adds support for newer types of processors 

In general, if your computer is incapable of using all the features of 

new software or hardware, you might need a BIOS upgrade.

70 

Chapter 3—BIOS Configurations and Upgrades 

Specific Tests to Determine Whether Your BIOS Needs 

an Update 

To determine whether your BIOS needs to be updated because of 

hard drive capacity limitations, see Chapter 4, “SCSI and IDE Hard 

Drives and Optical Drives.” 

To determine whether your BIOS needs to be updated because of 

operating system or CPU-upgrade issues, consult the technicalsupport 

Web sites for the operating system or CPU upgrade. 

If your computer was built before 1999 and you have not performed 

a BIOS upgrade or loaded year-2000 patches for your operating 

system and applications, you might have Y2K-related 

problems with accurate date handling. Because the RTC (Real-Time- 

Clock) on most computers doesn’t track centuries, the system BIOS 

must accurately add this information before handing the date to 

the operating system and applications, and the BIOS/RTC must also 

accurately handle leap years such as 2000 and beyond. A BIOS 

upgrade is the best way to handle RTC/BIOS issues, but software 

patches in the AUTOEXEC.BAT or CONFIG.SYS can also be used. 

Consult your operating system and application vendors for appropriate 

solutions, including software updates or replacement versions. 

Fixing BIOS Limitations—BIOS Fixes and Alternatives 

Use Table 3.1 to determine which options you can follow if a BIOS 

update isn’t possible, depending on the BIOS problem noted. 

Table 3.1 Alternatives to BIOS Upgrades 

Benefits of Limitations of 

Problem Alternative Fix Alternative Fix Alternative Fix 

Y2K date Install Y2K- Provides hardware Uses an ISA slot; doesn’t 

rollover compliant BIOS solution to non- handle problems with direct 

card. compliant BIOS; access to RTC that might 

can be combined be performed by some 

with fix for hard disk operating systems and 

capacity limitations. applications. 

Install Y2K- Provides hardware Uses an ISA slot; some 

compliant BIOS solution for both versions require that drivers 

and RTC card. BIOS and RTC Y2K. be installed for the operating 

system in use. 

Install Y2K- Low-cost or free Can be bypassed by bootcompliant 

TSR or solution that avoids ing off floppy; might not 

device driver. opening system. handle allY2K clock rollover 

problems; can be removed 

from boot process; not 

available for all operating 

systems.

Where BIOS Updates Come From 71 

Table 3.1 Alternatives to BIOS Upgrades Continued 

Benefits of Limitations of 

Problem Alternative Fix Alternative Fix Alternative Fix 

IDE hard disk See Chapter 4 for 

capacity details of these 

limitations fixes. 

Complete Replace Provides both brand- System must use standard 

solution motherboard. new BIOS and new MB form factor; mix of ISA 

motherboard features and PCI/AGP slots might 

at a price often just mean some existing cards 

slightly higher than a won’t fit because latest 

third-party BIOS motherboards have more 

upgrade. PCI than ISA slots; timeconsuming 

hardware install; 

requires time-consuming 

redetection and configuration 

of hardware drivers in 

operating system. 

How BIOS Updates Are Performed 

Two different ways of updating a motherboard BIOS are available. 

With older systems, a physical chip swap (also called a BIOS chip 

upgrade) is necessary. The original BIOS chip is removed, and a new 

BIOS chip is inserted in its place. The new BIOS must be customized 

to match the old system’s motherboard and chipset, use its 

existing CPU, and provide the enhanced features specified by the 

upgrade BIOS manufacturer. The typical cost range is around 

$60–90 for a single BIOS chip. 

With newer systems that have a flash-upgradable BIOS, the update 

software is downloaded and installed onto a disk, which is used to 

boot the computer. Then, the new BIOS code is copied to the BIOS 

chip in a process that takes about 3–5 minutes. If the BIOS update 

comes from a source other than the original system or motherboard 

maker, it will also cost as much as $90 for the update. 

In either case, the system might need to be reconfigured, especially 

if the new BIOS was physically installed, or if either a chip-based or 

flash-based BIOS is a different brand of BIOS than the original. 

Where BIOS Updates Come From 

The best (and cheapest!) place to get a BIOS update is from your 

motherboard or system vendor. Most major system manufacturers 

offer free BIOS updates for their systems with flash BIOS chips on 

their Web sites. For clone systems with motherboards from various 

producers, see the section “Determining Which BIOS You Have” 

later in this chapter.

72 

A second source for BIOS updates is from one of the following companies. 

For systems that originally used the Phoenix BIOS, contact Micro 

Firmware (www.firmware.com or 800-767-5465). Micro Firmware 

typically supplies updated Phoenix flash BIOS code on disk for systems 

they support. See the Web site for the current list of supported 

systems and motherboards. 

For systems that originally used the Award, AMI, MR BIOS, or 

Phoenix BIOS (including systems not supported by Micro 

Firmware), contact Unicore Software (www.unicore.com or 800- 

800-BIOS). Unicore might supply the update on disk or as a 

replacement MR BIOS chip. Contact these vendors for details and 

prices, which vary by system. 

Precautions to Take Before 

Updating a BIOS 

Use the following checklist to be safe, not sorry, when updating a 

BIOS. 

First, back up your data. An “almost working” BIOS that doesn’t 

quite work with your hard drive can blow away your data. 

Back up your current BIOS code if you can. Some BIOS update 

loader programs offer this option, but others don’t. As an alternative, 

some BIOS chips keep a mini-BIOS onboard that can be reactivated 

in the event that a botched update destroys the main BIOS. 

Some motherboards have a jumper that can be used to switch to 

the backup; check your system documentation. For others, check 

the Micro Firmware Web site for its Flash BIOS Recovery Disks page 

to find out whether your motherboard is listed. If the BIOS update 

isn’t completed properly, you could have a dead system that will 

need a trip to the manufacturer for repair. See the next section, 

“How to Recover from a Failed BIOS Update Procedure,” for a typical 

recovery procedure. 

Record your hard drive configuration information, including the 

following: 

• Cylinders 

• Heads 


• Sectors per Track 

• Translation (Normal, LBA [greater than 504MB], Large, and 

so on)

How to Recover from a Failed BIOS Update Procedure 73 

If you are switching to a different brand of BIOS, you might need 

to re-enter this information. 

Record other non-standard BIOS settings, such as hard disk transfer 

rate settings, built-in serial and parallel port settings, and so on. A 

worksheet you can use as a guide is found later in this chapter. 

Read carefully and completely the information provided with the 

flash BIOS download or chip-type BIOS update kit. Check online or 

call the BIOS manufacturer if you have any questions before you 

ruin your BIOS. 

Check to see whether your system has a write-protect setting jumper 

on the motherboard that must be adjusted to allow a BIOS update 

to take place. Some motherboards disable BIOS updates by default 

to protect your system’s BIOS from unauthorized changes. Set your 

motherboard to allow the change before you install the flash BIOS 

update, and reset the protection after the update is complete. 

How to Recover from a Failed BIOS 

Update Procedure 

Most motherboards with soldered-in flash ROMs have a special 

BIOS Recovery procedure that can be performed. This hinges on a 

special unerasable part of the flash ROM that is reserved for this 

purpose. 

In the unlikely event that a flash upgrade is interrupted catastrophically, 

the BIOS might be left in an unusable state. Recovering from 

this condition requires the following steps. A minimum of a power 

supply, a speaker, and a floppy drive configured as drive A: should 

be attached to the motherboard for this procedure to work: 

1. Change the Flash Recovery jumper to the recovery mode 

position. Virtually all Intel motherboards and many thirdparty 

motherboards have a jumper or switch for BIOS recovery, 

which is normally labeled Recover/Normal. 

2. Install the bootable BIOS upgrade disk you previously created 

to perform the flash upgrade into drive A: and reboot the 

system. 

Because of the small amount of code available in the nonerasable 

flash boot block area, no video prompts are available 

to direct the procedure. In other words, you will see nothing 

onscreen. In fact, it is not even necessary for a video card to 

be connected for this procedure to work. The procedure can 

be monitored by listening to the speaker and looking at the

74 

floppy drive LED. When the system beeps and the floppy 

drive LED is lit, the system is copying the BIOS recovery code 

into the flash device. 

3. As soon as the drive LED goes off, the recovery should be 

complete. Power the system off. 

4. Change the flash recovery jumper back to the default position 

for normal operation. 

When you power the system back on, the new BIOS should be 

installed and functional. However, you might want to leave the 

BIOS upgrade floppy in drive A: and check to see that the proper 

BIOS version was installed. 

Note 


Note that this BIOS recovery procedure is often the fastest way 

to update a large number of machines, especially if you are performing 

other upgrades at the same time. This is how it is normally 

done in a system assembly or production environment. 

Plug-and-Play BIOS 

The role of the traditional BIOS was to manage the essential devices 

in the system: the hard drive, floppy drive, video, parallel and serial 

ports, and keyboard and system timer. Other devices were left to 

fight for the remaining IRQs and other hardware resources listed in 

Chapter 2, “System Components and Configuration.” When 

Windows 95 was introduced, the role of the BIOS changed dramatically. 

To support Windows 95, the Plug-and-Play BIOS was introduced, 

changing how cards were installed and managed. Table 3.2 

compares a Plug-and-Play (PnP) BIOS to a conventional BIOS. 

Table 3.2 Plug-and-Play BIOS Versus Conventional BIOS 

Task Conventional BIOS Plug-and Play BIOS 

Hardware Motherboard-based All PnP devices as well as 

configuration devices and video only motherboard devices 

Configuration type Static (fixed settings) Dynamic (settings can be altered 

as various devices are installed) 

Configuration Manual configuration Manual, BIOS-assisted, or 

operating method system 

assisted 

Operating system Accepts all BIOS settings Receives PnP device information 

relationship to BIOS without alteration from BIOS and can alter settings 

as required

Note 

A complete list of PnP device IDs is found in the Technical 

Reference section of the CD included with Upgrading and 

Repairing PCs, 12th Edition. 

PnP BIOS Configuration Options 

Plug-and-Play BIOS 75 

While PnP BIOSes vary widely in their features, the following settings 

are typical. Use the list in Table 3.3 along with the tables that 

follow to help you make configuration changes when necessary. 

Resource Configuration 

The Resource Configuration menu is used for configuring the memory 

and interrupt usage of non–Plug-and-Play (legacy) ISA busbased 

devices. Table 3.3 shows the functions and options found in 

a typical modern BIOS. 

Table 3.3 Typical Resource Configuration Menu1 Feature Options Description 

Memory C800 CBFF Available (default) | Reserved Reserves specific upper 

Reservation CC00 CFFF Available (default) | Reserved memory blocks for use 

D000 D3FF Available (default) | Reserved 

D400 D7FF Available (default) | Reserved 

D800 DBFF Available (default) | Reserved 

DC00 DFFF Available (default) | Reserved 

by legacy ISA devices. 

IRQ IRQ 3 Available (default) | Reserved Reserves specific IRQs 

Reservation IRQ 4 Available (default) | Reserved for use by legacy ISA 

IRQ 5 Available (default) | Reserved devices. An asterisk (*) 

IRQ 7 Available (default) | Reserved displayed next to an IRQ 

IRQ 10 Available (default) | Reserved 

IRQ 11 Available (default) | Reserved 

indicates an IRQ conflict. 

1. Based on the Phoenix BIOS used by the Intel SE440BX2 motherboard. Used by permission of 

Intel Corporation. 

Note that these settings are only for legacy (non–Plug-and-Play) ISA 

devices. For all Plug-and-Play ISA devices, as well as PCI devices 

(which are Plug-and-Play by default), these resources are instead 

configured by the operating system or by software that comes with 

the cards. 

Setting these resources here does not actually control the legacy ISA 

device; that usually must be done by moving jumpers on the card. 

By setting the resource as reserved here, you are telling the Plugand-Play 

operating system that the reserved resources are off-limits, 

so it won’t accidentally set a Plug-and-Play device to use the same 

resource as a legacy ISA device. Reserving resources in this manner 

is sometimes required because the Plug-and-Play software can’t 

detect all legacy ISA devices and therefore won’t know which settings 

the device might be using.

76 


In a system with no legacy devices, reserving any resources via this 

menu is not necessary. 

Some boards have additional configuration options for the Plugand-Play 

(PnP) BIOS features as well as the PCI bus. These features 

are largely chipset dependent, but some common examples are 

shown in Table 3.4. 

Table 3.4 Typical PnP and PCI Options 1 

DMA n Assigned to When resources are controlled manually, assign each 

system DMA channel as one of the following types, 

depending on the type of device using the interrupt: 

• Legacy ISA devices compliant with the original 

PC AT bus specification, requiring a specific 

DMA channel 

• PCI/ISA PnP devices compliant with the Plugand-Play 

standard, whether designed for PCI 

or ISA bus architecture 

PCI IRQ Activated by Leave the IRQ trigger set at Level unless the PCI 

device assigned to the interrupt specifies edgetriggered 

interrupts. 

PCI IDE IRQ Map to This field enables you to select PCI IDE IRQ mapping 

or PC AT (ISA) interrupts. If your system does not 

have one or two PCI IDE connectors on the system 

board, select values according to the type of IDE 

interface(s) installed in your system (PCI or ISA). 

Standard ISA interrupts for IDE channels are IRQ 14 

for primary and IRQ 15 for secondary. 

Primary/Secondary IDE INT# Each PCI peripheral connection is capable of activating 

up to four interrupts: INT# A, INT# B, INT# C, 

and INT# D. By default, a PCI connection is assigned 

INT# A. Assigning INT# B has no meaning unless 

the peripheral device requires two interrupt services 

rather than one. Because the PCI IDE interface in the 

chipset has two channels, it requires two interrupt 

services. The primary and secondary IDE INT# fields 

default to values appropriate for two PCI IDE channels, 

with the primary PCI IDE channel having a 

lower interrupt than the secondary. 

Note that all single-function PCI cards normally use 

INT# A, and each of these must be assigned to a different 

and unique ISA interrupt request (IRQ). 

Used Mem base addr Select a base address for the memory area used by 

any peripheral that requires high memory. 

Used Mem Length Select a length for the memory area specified in the 

previous field. This field does not appear if no base 

address is specified. 

Assign IRQ for USB Select Enabled if your system has a USB controller 

and you have one or more USB devices connected. 

If you are not using your system’s USB controller, 

select Disabled to free the IRQ resource. 

1. Based on the Phoenix BIOS used by the Intel SE440BX2 motherboard. Used by permission of 

Intel Corporation.

Other BIOS Troubleshooting Tips 77 

When to Use the PnP BIOS Configuration Options 

In an ideal situation involving PnP-aware operating systems—such 

as Windows 9x or 2000, a computer with a PnP BIOS, and a PnP 

device—the BIOS detects the PnP device and Windows configures it 

without user intervention. Table 3.5 lists the circumstances under 

which you might need to use PnP BIOS configuration options. 

Table 3.5 Solving Configuration Problems with the PnP BIOS 

Configuration Options 

Problem Solution Notes 

Legacy (non-PnP) card Set DMA and IRQ used by This prevents PnP devices 

needs particular IRQ legacy card to “ISA” from using the resource; 

or DMA setting already option in BIOS. verify legacy card setting 

in use by PnP device. matches BIOS selections. 

Windows 9x/Me/2000 is not Set “Plug and Play Aware 

detecting and configuring Operating System” option 

PnP devices not needed at 

boot time (such as modems, 

printers, and so on). 

to “Yes” in BIOS. 

PCI video card is assigned Set “Assign IRQ to VGA” This frees up the IRQ withan 

IRQ that you need for option to “No” in BIOS. out ill effects in most 

another device. cases; might not work if the 

video card is used for MPEG 

movie playback. 

New PnP device can’t be Set “PCI Slot x IRQ Priority” If setting the IRQ for the PCI 

detected by system. to desired (unused) IRQ; slot doesn’t work, remove 

install card into designated all non-essential PnP cards, 

PCI slot. install new PnP card first, 

and then reinstall others. 

Other BIOS Troubleshooting Tips 

Use Table 3.6 to help solve some other typical system problems 

through BIOS configuration settings. 

Table 3.6 

Problems 

Troubleshooting Common BIOS-Related System 


Can’t access system Passwords are stored Remove battery on motherboard and 

because passwords in CMOS non-volatile wait for all CMOS settings to be lost 

for startup or setup RAM (NVRAM) and are or use MB jumper called “clear 

access aren’t known. configured through BIOS. CMOS”; before clearing CMOS, view 

bootup configuration information and 

note hard drive and other configuration 

information, because all setup 

information must be re-entered after 

CMOS is cleared.

78 


Table 3.6 Troubleshooting Common BIOS-Related System 

Problems Continued 


System wastes time Disable automatic drive 

detecting hard drives detection in BIOS; 

at every bootup. “lock in” settings for 

drives by using 

“detect drives” 

option in BIOS. 

System drops network Power management not Determine which IRQs are used 

or modem connection set correctly for IRQs by devices and adjust power 

when system is idle. in use by modem or management for those devices; 

network card. disable power management in BIOS. 

Parallel or serial port Change configuration in See Chapters 6 and 7 for details. 

conflicts. BIOS. 

For more about troubleshooting and adjusting BIOS configuration 

settings, see Chapter 5 of Upgrading and Repairing PCs, 12th Edition, 

published by Que. 

Soft BIOS CPU Speed and Multiplier 

Settings 

Conventional motherboards might require the user to configure 

CPU speed, FSB (motherboard or system bus) speed, and clock multipliers 

through a series of jumpers or switches or through BIOS 

configuration screens. One danger to BIOS configuration is that the 

user might create a configuration that won’t allow the system to 

boot, and might require the CMOS configuration to be deleted to 

enable the user to try another option. 

As an alternative, ABIT motherboards have pioneered BIOScontrolled 

configuration of CPU speeds, clock multipliers, FSB 

(motherboard/system bus) speeds, and other options using a feature 

called SoftMenu III that also enables hardware overrides. 

SoftMenu III enables users to do the following: 

• Adjust FSB speeds up to 200MHz 

• Adjust core voltage 

• Adjust AGP and PCI clock ratios 

If the user creates an “impossible” combination of settings that 

won’t permit the system to boot, a set of DIP switches on motherboards 

using SoftMenu III can override the BIOS configuration, 

enabling the system to boot.

Determining the Motherboard Manufacturer for BIOS Upgrades 79 

Determining Which BIOS You Have 

It’s important to know which BIOS brand and version a computer 

has for two reasons. 

First, in the event of a boot failure, BIOS error codes, which vary by 

brand and model, can be used to help you find the cause of the 

problem and lead you to a solution. 

Second, knowing which BIOS brand and version you have can 

enable you to get help from the BIOS or system vendor for certain 

chipset configuration issues. 

To determine which BIOS you have, use the following methods: 

• Watch your system startup screen for information about the 

BIOS brand and version, such as “Award BIOS v4.51PG.” 

• Use a hardware test-and-reporting utility, such as Microsoft’s 

venerable MSD.EXE, AMIDiag, CheckIt, or others. 

Note that the best source for machine-specific information about 

error codes and other BIOS issues is your system manufacturer. 

Major vendors, such as IBM, Dell, Compaq, Gateway, Hewlett- 

Packard, and others, maintain excellent Web sites that list specific 

information for your system. However, if you are working with a 

white-box clone system made from generic components, BIOS-level 

information might be the best information you can get. 

Determining the Motherboard 

Manufacturer for BIOS Upgrades 

While knowing the BIOS brand and version is sufficient for troubleshooting 

a system that won’t start, solving problems with issues 

such as year-2000 compliance, large hard disk support, and power 

management requires knowing exactly which motherboard you 

have and who produced it. Because motherboard manufacturers 

tailor BIOS code to the needs of each motherboard model, the 

motherboard or system vendor—not the BIOS vendor—is the 

source to turn to for BIOS upgrades and other BIOS configuration 

issues. 

Identifying Motherboards with AMI BIOS 

Motherboards using AMI BIOS versions built from 1991 to the present 

(AMI’s High-Flex BIOS or WinBIOS) display a long string of 

numbers at the bottom of the first screen that is displayed when 

the system is powered on or restarted: 

51-0411-001771-00111111-071595-82439HX-F

80 


Interpret a number such as this one with the following numerical 

key (see Table 3.7): 

AB-CCCC-DDDDDD-EFGHIJKL-mmddyy-MMMMMMM-N 

Table 3.7 AB-CCCC-DDDDDD-EFGHIJKL-mmddyy-MMMMMMM-N 

Position Description 

A Processor Type: 

0 = 8086 or 8088 

2 = 286 

3 = 386 

4 = 486 

5 = Pentium 

6 = Pentium Pro/II 

B Size of BIOS: 

0 = 64KB BIOS 

1 = 128KB BIOS 

CCCC Major and minor BIOS version number 

DDDDDD Manufacturer license code reference number: 

0036xx = AMI 386 motherboard, xx = Series # 

0046xx = AMI 486 motherboard, xx = Series # 

0056xx = AMI Pentium motherboard, xx = Series # 

0066xx = AMI Pentium Pro motherboard, xx = Series # 

(for other numbers see the following note) 

E 1 = Halt on POST Error 

F 1 = Initialize CMOS every boot 

G 1 = Block pins 22 and 23 of the keyboard controller 

H 1 = Mouse support in BIOS/keyboard controller 

I 1 = Wait for F1 key on POST errors 

J 1 = Display floppy error during POST 

K 1 = Display video error during POST 

L 1 = Display keyboard error during POST 

mmddyy BIOS Date, mm/dd/yy 

MMMMMMM Chipset identifier or BIOS name 

N Keyboard controller version number

Determining the Motherboard Manufacturer for BIOS Upgrades 81 

Note 

Use the following resources to determine the manufacturer of 

non-AMI motherboards using the AMI BIOS: 

AMI has a listing of U.S. and non-U.S. motherboard manufacturers 

at the following address: 

http://www.ami.com/amibios/support/identify.html 

AMI also offers a downloadable utility program called AMIMBID 

for use with Windows 9x/2000/NT and MS-DOS. Follow the AMI 

Motherboard Identification Utility link from the AMI Technical 

Support page, available as a link from the following address: 

http://www.ami.com 

A more detailed listing, including complete identification of particular 

motherboard models, is available at Wim’s BIOS page 

(www.ping.be/bios). This site also has links to motherboard 

manufacturers for BIOS upgrades. 

Identifying Motherboards with Award BIOS 

Motherboards with the Award Software BIOS also use a numerical 

code, although the structure is different from that for the AMI Hi- 

Flex BIOS. 

The following is a typical Award BIOS ID: 

2A59IABDC-00 

The sixth and seventh characters (bolded for emphasis) indicate the 

motherboard manufacturer, whereas the eighth character can be 

used for the model number or the motherboard family (various 

motherboards using the same chipset). 

Note 

For lookup tables of these codes, see the following Web sites: 

Award Software’s official table for manufacturers only is available 

at www.phoenix.com/pcuser/bios-award-vendors.html. 

An expanded list, also containing chipset information (stored in 

the first five characters of the Award BIOS ID), is available at 

Wim’s BIOS site (www.ping.be/bios/).

82 


Identifying Motherboards with Phoenix or Microid 

Research BIOS 

Unfortunately, neither Phoenix nor Microid Research (MR BIOS) 

use any type of a standardized motherboard ID number system. 

For systems using a Phoenix BIOS, see whether your motherboard 

or system is listed on the Micro Firmware BIOS upgrades page. 

Links from this page for Intel and Micronics motherboards list the 

codes that show up onscreen during boot. Match these codes to 

your system and you might be able to use a Micro Firmware 

upgrade. Most MR BIOS (Microid Research BIOS) installations are 

done as upgrades rather than in original equipment. See the list of 

supported chipsets (identified by chipset brand and model, not 

motherboard vendor) and motherboards using Intel’s Triton-series 

chipsets to see whether your system can use an MR BIOS, or contact 

Microid Research directly for system-specific information. 

Accessing the BIOS Setup Programs 

The BIOS is configured in one of several ways. Early computers, 

such as the IBM PC and PC/XT, used DIP switches on the motherboard 

to set a limited range of BIOS options, including memory 

size and the number of floppy disk drives. The IBM PC/AT introduced 

a disk-based configuration utility to cope with the many 

additional options on 286-based CPUs. Since the late 1980s, most 

computers have had their BIOS Setup programs incorporated into 

the BIOS chip itself. The Setup program is accessed on these systems 

by pressing a key or key combination early in the system 

startup procedure. Most recent computers display the correct keystroke(s) 

to use during the system startup. If not, use Table 3.8 to 

learn the keystrokes used to start common BIOS types. 

Table 3.8 

Program 

Common Keystrokes Used to Access the BIOS Setup 

BIOS Keystrokes Notes 

Phoenix BIOS Ctrl+Alt+Esc 

Ctrl+Alt+F1 

Ctrl+Alt+S 

Ctrl+Alt+Enter 

Ctrl+Alt+F11 

Ctrl+Alt+Ins 

Award BIOS Ctrl+Alt+Esc 

Esc 

AMI BIOS Del

Table 3.8 Common Keystrokes Used to Access the BIOS Setup 

Program Continued 

BIOS Keystrokes Notes 

IBM BIOS Ctrl+Alt+Ins*F1 *—Early notebook models; press when cursor 

is in upper-right corner of screen 

Compaq BIOS F10* Keystroke actually loads Compaq Setup program 

from hard disk partition; press when 

cursor is in upper-right corner of screen 

Note 


See Chapter 5 of Upgrading and Repairing PCs, 12th Edition to 

see how a typical BIOS Setup program operates. 

How the BIOS Reports Errors 

The BIOS will use three methods for reporting errors: beep codes, 

error/status codes, and onscreen messages. Error/status codes must 

be read with a special interface board, whereas the others require 

no special equipment. 

BIOS Beep Codes and Their Purposes 

Virtually all systems make a polite “beep” noise when started, but 

most systems have a special series of beep codes that serve the following 

purposes. 

Beeps alert you to serious system problems, many of which can prevent 

your system from even starting (a so-called fatal error) or from 

working to its full potential (a so-called non-fatal error). 

Because most fatal and many non-fatal errors take place before the 

video subsystem is initialized (or might indicate the video isn’t 

working), beeps can be used to determine the cause of the problem. 

A system that can’t start and is reporting a problem with beep 

codes will give the code once and then halt. To hear the code 

again, restart the computer. 

Use the following tables of beep codes to determine why your system 

will not start. To solve the problem reported by the beep codes, 

repair or replace the device listed in the description. If your repair 

or replacement has solved the problem, the beep code will no 

longer sound when you restart the system. 

For errors involving removable devices (socketed chips, memory, or 

video), an easy fix is to remove and replace the item because a 

device that’s not securely in its socket will cause the test to fail.

84 

Note 

For an exhaustive list of BIOS codes, beep codes, and error messages, 

see the CD accompanying Upgrading and Repairing PCs, 

12th Edition. 

AMI BIOS Beep Codes 

Note 


AMI BIOS beep codes used by permission of American 

Megatrends, Inc. 

Beeps Error Message Description 

1 DRAM Refresh Failure The memory refresh circuitry on the motherboard 

is faulty. 

2 Parity Error A parity error occurred in system memory. 

3 Base 64KB (First Bank) 

Memory Failure 

Memory failure in the first bank of memory. 

4 System Timer Failure Memory failure in the first bank of memory, 

or Timer 1 on the motherboard is not functioning. 

5 Processor Error The processor on the motherboard generated 

an error. 

6 Keyboard Controller Gate The keyboard controller might be bad. The 

A20 Failure BIOS cannot switch to protected mode. 

7 Virtual Mode Processor The processor generated an exception 

Exception Interrupt Error interrupt. 

8 Display Memory Read/Write The system video adapter is either missing 

Error or its memory is faulty. 

9 ROM Checksum Error ROM checksum value does not match the 

value encoded in BIOS. 

10 CMOS Shutdown Register The shutdown register for CMOS RAM 

Read/Write Error failed. 

11 Cache Error/L2 Cache Bad The L2 cache is faulty. 

1 long, Conventional/extended The motherboard memory is faulty. 

3 short memory failure 

1 long, Display/retrace test The video card is faulty; try reseating or 

8 short failed moving to a different slot. 

Award BIOS Beep Codes 

Currently only one beep code exists in the Award BIOS. A single 

long beep followed by two short beeps indicates that a video error 

has occurred and the BIOS cannot initialize the video screen to display 

any additional information.

Phoenix BIOS Beep Codes 

The following beep codes are for the current version of Phoenix 

BIOS, version 4.0, release 6. Other versions will have somewhat different 

beeps and Port 80h codes. To view the Port 80h codes, you 

will need a POST diagnostics card with a two-digit LED readout, 

available from many sources for diagnostic tools. I recommend a 

PCI-based POST card because ISA slots are becoming obsolete. 

Note 

Phoenix BIOS beep codes used by permission of Phoenix 

Technologies, Ltd. 

Beeps Port 80h Code Explanation 

1-2-2-3 16h BIOS ROM checksum 

1-3-1-1 20h Test DRAM refresh 

1-3-1-3 22h Test keyboard controller 

1-3-3-1 28h Autosize DRAM 

1-3-3-2 29h Initialize POST memory manager 

1-3-3-3 2Ah Clear 512KB base RAM 

1-3-4-1 2Ch RAM failure on address line xxxx 

1-3-4-3 2Eh RAM failure on data bits xxxx of low byte of memory 

bus 

1-4-1-1 30h RAM failure on data bits xxxx of high byte of 

memory bus 

2-1-2-2 45h POST device initialization 

2-1-2-3 46h Check ROM copyright notice 

2-2-3-1 58h Test for unexpected interrupts 

2-2-4-1 5Ch Test RAM between 512KB and 640KB 

1-2 98h Search for option ROMs; one long, two short 

beeps on checksum failure 

1 B4h One short beep before boot 

IBM BIOS Beep and Alphanumeric Error Codes 

After completing the power on self test (POST), an audio code indicates 

either a normal condition or that one of several errors has 

occurred. 

Note 


IBM BIOS and alphanumeric error codes used by permission 

of IBM.

86 

Audio Code Sound Graph Description 

1 short beep • Normal POST—system okay 

2 short beeps •• POST error—error code on display 

No beep Power supply, system board 

Continuous beep ————— Power supply, system board 

Repeating short beeps •••••• Power supply, system board 

1 long, 1 short beep -• System board 

1 long, 2 short beeps -•• Video adapter (MDA/CGA) 

1 long, 3 short beeps -••• Video adapter (EGA/VGA) 

3 long beeps - - - 3270 keyboard card 

Microid Research Beep Codes 

The MR BIOS generates patterns of high and low beeps to signal an 

error condition. 

The following beep codes are for the current and recent versions 

(3.x) of the MR BIOS. 

Note 


MR BIOS beep codes used by permission of Phoenix 

Technologies, Ltd. 

Port 80h Beep 

Code Codes Error Messages 

03h LH-LLL ROM-BIOS Checksum Failure 

04h LH-HLL DMA Page Register Failure 

05h LH-LHL Keyboard Controller Selftest Failure 

08h LH-HHL Memory Refresh Circuitry Failure 

09h LH-LLH Master (16-bit) DMA Controller Failure 

09h LH-HLH Slave (8-bit) DMA Controller Failure 

0Ah LH-LLLL Base 64KB Pattern Test Failure 

0Ah LH-HLLL Base 64KB Parity Circuitry Failure 

0Ah LH-LHLL Base 64KB Parity Error 

0Ah LH-HHLL Base 64KB Data Bus Failure 

0Ah LH-LLHL Base 64KB Address Bus Failure 

0Ah LH-HLHL Base 64KB Block Access Read Failure 

0Ah LH-LHHL Base 64KB Block Access Read/Write Failure 

0Bh LH-HHHL Master 8259 (Port 21) Failure 

0Bh LH-LLLH Slave 8259 (Port A1) Failure 

0Ch LH-HLLH Master 8259 (Port 20) Interrupt Address Error

Port 80h Beep 

Code Codes Error Messages 

0Ch LH-LHLH Slave 8259 (Port A0) Interrupt Address Error 

0Ch LH-HHLH 8259 (Port 20/A0) Interrupt Address Error 

0Ch LH-LLHH Master 8259 (Port 20) Stuck Interrupt Error 

0Ch LH-HLHH Slave 8259 (Port A0) Stuck Interrupt Error 

0Ch LH-LHHH System Timer 8254 CH0/IRQ 0 Interrupt Failure 

0Dh LH-HHHH 8254 Channel 0 (System Timer) Failure 

0Eh LH-LLLLH 8254 Channel 2 (Speaker) Failure 

0Eh LH-HLLLH 8254 OUT2 (Speaker Detect) Failure 

0Fh LH-LHLLH CMOS RAM Read/Write Test Failure 

0Fh LH-HHLLH RTC Periodic Interrupt/IRQ 8 Failure 

10h LH-LLHLH Video ROM Checksum Failure at Address XXXX, Mono 

Card Memory Error at Address XXXX, Mono Card Memory 

Address Line Error at Address XXXX, Color Graphics Card 

Memory Error at Address XXXX, Color Graphics Card 

Address Line Error at Address XXXX 

11h none Real Time Clock (RTC) Battery is Discharged 

11h none Battery Backed Memory (CMOS) is Corrupt 

12h LH-HLHLH Keyboard Controller Failure 

14h LH-LHHLH Memory Parity Error_18h_19h 

Microid Research Beep Codes 87 

14h LH-HHHLH I/O Channel Error_18h_19h 

14h none RAM Pattern Test Failed at XXXX, Parity Circuit Failure 

18h in Bank XXXX, Data Bus Test Failed: Address XXXX, 

19h Address Line Test Failed at XXXX, Block Access Read Failure 

at Address XXXX, Block Access Read/Write Failure: Address 

XXXX, Banks Decode to Same Location: XXXX and YYYY 

12h none Keyboard Error—Stuck Key Keyboard Failure or no 

15h Keyboard Present 

17h LH-LLLHH A20 Test Failure Due to 8042 Timeout 

17h LH-HLLHH A20 Gate Stuck in Disabled State (A20=0) 

17h none A20 Gate Stuck in Asserted State (A20 Follows CPU) 

1Ah LH-LHLHH Real Time Clock (RTC) is Not Updating 

1Ah none Real Time Clock (RTC) Settings are Invalid 

1Eh none Disk CMOS Configuration is Invalid, Disk Controller Failure, 

Disk Drive A: Failure, Disk Drive B: Failure 

1Fh none Fixed Disk CMOS Configuration is Invalid, Fixed Disk 

C:(80) Failure, Fixed Disk D:(81) Failure, Please Wait for 

Fixed Disk to Spin Up 

20h none Fixed Disk, Disk, Serial Port, Parallel Port, Video, Memory, 

or Numeric Coprocessor Configuration Change 

21h none System Key is in Locked Position—Turn Key to Unlocked 

Position 

29h none Adapter ROM Checksum Failure at Address XXXX 

Note for beep codes: L=low tone and H=high tone

88 


Reading BIOS Error Codes 

Because beep codes can indicate only some of the problems in a 

system at startup, most BIOSes also output a series of status codes 

during the boot procedure. These codes are sent to an I/O port 

address that can be read by specialized diagnostic cards, which you 

can purchase from many different vendors. These POST cards (so 

named from the power on self test) feature a two-digit LED panel 

that displays the status codes output by the BIOS. The simpler 

POST cards are hard-wired to pick up signals from the most commonly 

used I/O port address 80hex, but more expensive models 

can be adjusted with jumper blocks to use other addresses used by 

certain BIOSes (such as Compaq). 

These cards are normally sold with manuals that list the error/status 

codes. While the cards are durable, the codes can become outdated. 

To get an updated list of codes, contact the system or BIOS 

vendor’s Web site. 

Most POST cards have been based on the ISA bus, but the latest 

models are now being made to fit into PCI slots because ISA is 

becoming obsolete. For diagnosing portable systems, and to avoid 

the need to open a system to insert a POST card, Ultra-X offers a 

MicroPOST display unit that attaches to the parallel port. Contact 

Ultra-X at www.uxd.com for more information. 

Onscreen Error Messages 

An onscreen error message is often the easiest of the error methods 

to understand, because you don’t need to count beeps or open the 

system to install a POST card. However, because some systems use 

numeric error codes, and even “plain English” codes need interpretation, 

these messages can still be a challenge to interpret. Because 

the video circuits are tested after components such as the motherboard, 

CPU, and BIOS, an onscreen error message is usually indicative 

of a less-serious error than one that is reported with beep 

codes. 

Interpreting Error Codes and Messages 

Because beep codes, error/status codes, and onscreen messages vary 

a great deal by BIOS vendor (and sometimes BIOS model), you 

must know what BIOS a system has before you can choose the correct 

table. With major-brand systems (and some others), you’ll typically 

find a list of error codes and messages in the system 

documentation. You can also contact the BIOS or system vendors’ 

Web sites for this information, or check on the CD included with 

Upgrading and Repairing PCs, 12th Edition.


BIOS Configuration Worksheet 

BIOS configuration options vary a great deal, and incorrect settings 

can cause a system to fail, lose data, or not work correctly with PnPcompatible 

operating systems, such as Windows 9x/2000/Me. The 

following worksheet can be used to record the most critical BIOS 

configuration information. Use it when you are unable to print out 

the actual configuration screens. 

System ID_____________________Brand & Model # ____________ 

Date Recorded_________________Operating System____________ 

Hard Disk Partitions______________________________________ 

Notes_____________________________________________________ 

__________________________________________________________ 

Standard CMOS/BIOS Configuration 

(Configuration Option) (Setting—circle or write down setting 

used) 

Drive A 1.44MB 

2.88MB 

Other__________ 

None 

Drive B 1.44MB 

2.88MB 

Other__________ 

None 

1st IDE Drive Drive Type: 

Hard Disk 

CD-ROM 

Other (specify) 

_____________ 

Hard disk Geometry 

Cyl:_________ 

Sectors/Track: ____ 

Heads: ________ 

LBA Y/N: 

2nd IDE Drive Drive Type: 

Hard Disk 

CD-ROM 


_____________ 


Cyl:_________

90 


Standard CMOS/BIOS Configuration 


Heads: ________ 

LBA Y/N: 

3rd IDE Drive Drive Type: 

Hard Disk 

CD-ROM 


_____________ 


Cyl:_________ 


Heads: ________ 

LBA Y/N: 

4th IDE Drive Drive Type: 

Hard Disk 

CD-ROM 


_____________ 


Cyl:_________ 


Heads: ________ 

LBA Y/N: 

Other BIOS Configuration Screens 

Boot Sequence 1st drive: _____ 

2nd drive:______ 

3rd drive:______ 

4th drive:______ 

Anti-Virus or Write-Protect Enable / Disable 

Boot Sector 

PS/2 Mouse Enable / Disable 

Password Power On 

Password: ________ 

Setup 

Password: ________ 

External Memory Cache Enable / Disable 

(Level 2) 

Internal Memory Cache Enable / Disable 

(Level 1)


Shadow RAM / ROM Shadowing Specify Range(s) In Use: 

_____________ 

_____________ 

_____________ 

_____________ 

USB Ports Enable / Disable 

USB Legacy Support Enable / Disable 

(keyboard & mouse) 

Memory Timing Configuration Auto / Manual 

If Manual, specify changes from system default 

below: 

_______________ 

_______________ 

_______________ 

_______________ 

_______________ 

Power Management Enable / Disable 

If Enabled, specify changes from system default 

below: 

_______________ 

_______________ 

_______________ 

_______________ 

_______________ 

Plug and Play (PnP) Enable / Disable 

If Enabled, specify changes from system default 

below: 

_______________ 

_______________ 

_______________ 

_______________ 

_______________ 

LPT Port Mode Selected: 

Standard EPP ECP Bi-Di 

Disabled 

EPP Version # _______ 

IRQ: 7 5 _______ 

DMA for ECP Mode: _____ 

I/O Port Address: 

378H

92 


LPT Port Mode Selected: 

278H 

3BCH 

Disabled 

Serial (COM) Port 1 I/O Port Address: 

3FH (COM1) 

2FH (COM2) 

3EH (COM3) 

2EH (COM4) 

Disabled 

Notes: ___________________ 

Serial (COM) Port 2 I/O Port Address: 

3FH (COM1) 

2FH (COM2) 

3EH (COM3) 

2EH (COM4) 

Disabled 

Notes: ___________________ 

IDE Hard Disk Interface #1 Interface: 

Enable / Disable 

32-bit Mode: Enable / Disable 

PIO Mode: 0 1 2 3 4 

UDMA Mode: 33MHz 66MHz 100MHz 

Block Mode: Enable / Disable 

# of Blocks: ____________ 

IDE Hard Disk Interface #2 Interface: 

Enable / Disable 

32-bit Mode: Enable / Disable 

PIO Mode: 0 1 2 3 4 

UDMA Mode: 33MHz 66MHz 100MHz 

Block Mode: Enable / Disable

4 

SCSI and IDE Hard 

Drives and Optical 

Drives 

Chapter 4 

Understanding Hard Disk 

Terminology 

When installing IDE hard disks in particular, at least three parameters 

must be indicated in the BIOS Setup program to define a hard 

disk. 

Note 

Understanding how hard drives store data is an enormous topic. 

If you’d like to learn more, see Chapters 9 and 10 of Upgrading 

and Repairing PCs, 12th Edition, also published by Que. 

Heads, Sectors per Track, and Cylinders 

If this information is not accurately listed in the BIOS configuration, 

the full capacity of the drive will not be available unless special 

hard disk drivers or supplementary BIOS cards are used. 

Whenever possible, the computer’s own ROM BIOS should fully 

support the drive’s capacity. 

For drives larger than 504MB (binary) or 528 million bytes, additional 

translation options are also required with MS-DOS and 

Windows to achieve full capacity. 

Hard Drive Heads 

A hard drive is comprised of one or more platters, normally made 

of aluminum but occasionally made of glass. These platters are covered 

with a thin rigid film of magnetized material. The magnetic 

structures of the platters are read or changed by read/write heads 

that move across the surface of the platters but are separated from 

it by a thin cushion of air. Virtually all platters are read from both 

sides. 

Sectors per Track 

The magnetic structures stored on the hard disk platters are organized 

into sectors of 512 data bytes each, plus additional areas in

94 

Chapter 4—SCSI and IDE Hard Drives and Optical Drives 

each sector for identifying the sector location on the hard disk. 

These sectors form concentric circles numbering from the outside 

of each platter to the hub area of the platter. 

Cylinders 

The third factor used to calculate the size of the hard disk is the 

number of cylinders on the hard disk. The identically positioned 

tracks on each side of every platter together make up a cylinder. 

The BIOS calculates the size of the hard disk in MB—or more often 

today, GB—from the number of cylinders, the number of heads, 

and the number of sectors per track. Most BIOSs make this calculation 

in binary MB or GB (the same way as the hard disk preparation 

program FDISK does), but a few make the calculation in 

decimal MB or GB (see Chapter 1, “General Technical Reference,” 

for the differences in these numbering methods). BIOSs that use 

decimal MB or GB calculations report the size of the drive the same 

way that drive manufacturers do. Either way, the same number of 

bytes will be available if the drive is fully and accurately handled 

by the ROM BIOS and operating system. Most recent and current 

drives print the cylinder, head, and sectors per track information 

(collectively called the drive’s geometry) on a label on the top of the 

drive for easy reference during installation. 

Note that all three elements of the drive geometry are actually logical, 

not physical, on IDE drives. This factor explains why the geometry 

can be translated (see the following), and why some IDE drives 

in older machines are working, despite being installed with “incorrect” 

geometries. 

Use the worksheet at the end of Chapter 3, “BIOS Configurations 

and Upgrades,” to record your hard drive geometry and other information 

for each system you manage. 

IDE Hard Drive Identification 

Integrated Drive Electronics (IDE), more properly called ATA drives 

(AT Attachment), are the overwhelming favorite for client PC 

installations. Although SCSI hard drives (see the following) offer 

benefits for network and high-performance workstation use, the 

combination of constantly-improving performance, rock bottom 

pricing per MB (under 1 cent and falling!), and enormous capacities 

(up to 75GB and climbing) will continue to make IDE/ATA drives 

the choice of most users. Figure 4.1 shows the typical IDE drive 

connectors.

Cable key prevents 

improperly plugging 

it into the drive 

IDE connector 

Stripe on 

interface cable 

denotes Pin 1 

Figure 4.1 Typical ATA (IDE) hard drive connectors. 

Master and Slave Drives 

As Figure 4.2 demonstrates, virtually every IDE drive interface is 

designed to handle two drives with a single 40-pin interface cable. 

Because the cable has no twist, unlike a typical 34-pin floppy interface 

cable, jumper blocks must be used on each hard drive to distinguish 

between the first (or master) drive on the cable and the 

second (or slave) drive on the cable. 

Most IDE drives can be configured with four possible settings: 

• Master (single-drive), also called Single 

• Master (dual-drive) 

• Slave (dual-drive) 

• Cable Select 

4 3 2 1 

Pin 1 

Master and Slave Drives 95 

Power cable 

RED(+5V) 

BLACK(Gnd) 

BLACK(Gnd) 

YELLOW(+12V) 

For virtually all systems, the Cable Select setting can be ignored 

because it must be used with a non-standard IDE cable. Thus, only 

three settings are really used, as seen in Table 4.1.

96 


10-pin Drives 6-pin Drives 

9 7 5 3 1 

10 8 6 4 2 

9 7 5 3 1 

10 8 6 4 2 

9 7 5 3 1 

10 8 6 4 2 

9 7 5 3 1 

10 8 6 4 2 

9 7 5 3 1 

10 8 6 4 2 

Figure 4.2 ATA (IDE) cable. 

5 3 1 

6 4 2 

5 3 1 

6 4 2 

5 3 1 

6 4 2 

5 3 1 

6 4 2 

5 3 1 

6 4 2 

Single 

(Neutral Postition) 

Table 4.1 Jumper Settings for Typical ATA IDE-Compatible Drives 

Jumper Name Single-Drive Dual-Drive Master Dual-Drive Slave 

Master (M/S) On or off 1 On Off 

Slave Present (SP) Off On Off 

1. Varies with drive; check user documentation. 

Single Drive 

(Standard Installation) 

Two Drives 

(Master) 

Two Drives 

(Slave) 

Cable Select (CS) 

Use Table 4.1 as a general guideline only. Follow your drive manufacturer’s 

recommendations if they vary. 

The jumpers on the hard drive might be located on the back of the 

drive (between the power and data connectors) or on the bottom of 

the drive. Typical hard disk jumpers are shown in Figure 4.3.

Breaking the 504MB (528-Million-Byte) Drive Barrier 97 

Figure 4.3 ATA (IDE) drive jumpers. Many drives now have eight, nine, 

or ten jumper pins to allow for special configurations required on some systems 

to break the 528-million-byte drive barrier (see the following sections). 

Breaking the 504MB (528-Million- 

Byte) Drive Barrier 

Because IDE was developed in the late 1980s, the combination of 

MS-DOS’s limit of 1,024 cylinders, the standard BIOS’s limit of 16 

heads, and the IDE interface’s limitation of 63 sectors per track limited 

the original size of IDE drives to 504MB (about 528 million 

bytes). This limit was merely theoretical until 1994, when IDE 

drives larger than this began to appear. A revised version of the 

IDE/ATA standard, ATA-2 (also called enhanced IDE) defined an 

enhanced BIOS to avoid these limits. 

An enhanced BIOS circumvents the limits by using a different 

geometry when talking to the drive than when talking to the software. 

What happens in between is called translation. For example, 

if your drive has 2,000 cylinders and 16 heads, a translating BIOS 

will make programs think that the drive has 1,000 cylinders and 

32 heads. The most common translation methods are listed in 

Table 4.2. These methods are also followed by newer versions of 

the ATA specification, such as ATA-3 and above. 

Table 4.2 ATA-2 Translation Methods 

BIOS Mode Operating System to BIOS BIOS to Drive Ports 

Standard CHS Logical CHS Parameters Logical CHS Parameters 

Extended CHS Translated CHS Parameters Logical CHS Parameters 

LBA Translated CHS Parameters LBA Parameters

98 


A BIOS that supports only Standard CHS recognizes only a maximum 

of 1,024 cylinders, 16 heads, and 63 sectors per track for any 

IDE/ATA drive. Thus, if you install a 6.4GB IDE/ATA drive in a system 

with this type of BIOS, it will recognize only 504MB with MS- 

DOS and Windows. Non-DOS operating systems such as Novell 

NetWare, UNIX, and Linux don’t require translation if they will be 

the only operating system on the disk partition. 

On systems that provide translation, this BIOS mode is called 

Normal because the geometry isn’t changed. Configuring a drive to 

use Normal mode is correct for operating systems such as UNIX, 

Linux, and Novell NetWare, but not for systems that use MS-DOS 

file structures, including MS-DOS itself, Windows 9x/NT/2000/Me, 

and OS/2. 

The other two modes, Extended CHS and LBA (Logical Block 

Addressing), do translate the geometry. Extended CHS is also called 

Large mode and is recommended only for >504MB drives that cannot 

be operated in LBA mode. Most enhanced BIOSs don’t offer 

Large mode, but all offer LBA mode. However, a few (such as older 

Acer BIOSs) might call it something different, such as DOS mode or 

>504MB mode. 

Using LBA Mode 

LBA mode can be enabled in two ways, depending on the BIOS. On 

most current BIOSs, using the automatic detection option in the 

BIOS or during system boot will detect the basic hard drive geometry 

and select LBA mode automatically. On some BIOSs, though, 

the automatic detection sets up the basic cylinder-head-sectors per 

track drive geometry but doesn’t enable LBA mode unless you set it 

yourself. Depending on the BIOS release used by a given system, 

the LBA mode setting can be performed on the same BIOS configuration 

screen used for standard drive configuration, or it might be 

located on an Advanced CMOS configuration or Peripheral Setup 

screen. 

A BIOS that performs LBA translation should enable you to use an 

IDE hard drive as large as 8.4GB with MS-DOS. If you find that you 

can use a 2.1GB hard disk, but not larger ones, the version of LBA 

mode supported by your BIOS is a very early version, and your 

BIOS should be updated. Support for drives larger than 8.4GB is 

discussed later in this chapter. 

When LBA Mode Is Necessary—and When Not to Use It 

Use Table 4.3 to determine when to use LBA mode.

Table 4.3 Using LBA Mode 

Operating 

Drive Size System Use LBA Mode Reason 


504MB MS-DOS, Yes Drive will be limited to 

Windows 9x/ 504MB without LBA 

NT/2000, OS/2 mode because of 1,024cylinder 

limit 

>504MB Linux, UNIX, No No 1,024-cylinder limit 

Novell NetWare with these operating systems 

Problems with LBA Support in the BIOS 

Ideally, LBA mode would be automatically enabled in a clearly 

understood way on every system with an enhanced BIOS. And, it 

would also be easy to know when you did not need to use it. 

Unfortunately, this is often not the case. 

Many 1994–1996 versions of the AMI text-based and graphical 

(WinBIOS) BIOSs listed the basic hard drive geometry on one 

screen and listed the LBA mode option on a different screen altogether. 

To make matters worse, the automatic drive setup options 

on many of these BIOSs didn’t set the LBA mode for you; you had 

to find it and then set it. But perhaps the worst problem of all was 

for users who had carefully set the LBA mode and then ran into 

problems with other BIOS configurations. Most AMI BIOS versions 

offer a feature called Automatic configuration with either 

BIOS/Optimal defaults (high performance) or Power-On/Fail-Safe 

defaults (low performance). In AMI BIOSs in which the LBA mode 

was not listed on the same screen with the hard disk geometry, any 

automatic configuration would reset LBA mode to its default 

setting—off. 

Because the location of the LBA setting can vary from system to 

system, always verify that LBA mode is still enabled if you make 

any changes to a BIOS configuration on systems that use LBA 

mode. 

Dangers of Altering Translation Settings 

Depending on the operating system and drive configuration, one of 

several unpleasant events takes place when LBA translation is 

turned off after a drive is configured using LBA. Table 4.4 summarizes 

these problems—some of which can be fatal to data!

100 


Table 4.4 Problems Associated with Disabling LBA Mode 

Drive Operating 

Configuration System Symptom End Result 

C: and D: MS-DOS Can’t access Usually no harm 

partitions D: because to data, because 

on single part of it drive is inaccessible 

physical drive is beyond until LBA mode 

cylinder 1024. is reset 

C: or C:, D:, etc. Windows 9x, Can’t boot Usually no harm 

Windows 2000, drive because to data because 

Windows NT, of incorrect drive is inaccessible 

Windows Me geometry. until LBA mode is 

reset 

C: only MS-DOS System boots Drive wraps around 

and operates to cylinder 0 

normally until (location of 

data is written partition 

to a cylinder table and other 

beyond 1024. vital disk structures) 

because LBA translation 

to access 

cylinders past 1024 

is absent; drive 

overwrites beginning 

of disk, causing 

loss of all data 

I used the last scenario in a computer troubleshooting class a few 

times, and it was quite a surprise to see a hard disk “eat” itself! 

However, it is never a good idea to “play” with LBA translation 

after it has been set in a system. 

Detecting Lack of LBA Mode Support in Your System 

To determine whether your system lacks LBA support or doesn’t 

have LBA support enabled, do the following: 

1. Install the hard drive set for Master, Slave, or Cable Select as 

appropriate. 

2. Turn on the computer and detect the drive in the BIOS Setup 

program. Note the size of the drive reported. 

3. Boot the computer from a floppy disk containing the operating 

system and FDISK. 

4. Select the drive you want to view with option #5.

5. Use the #4 option—View Current Partitions—and check 

what capacity FDISK reports. 

6. If FDISK reports the drive size as only 504MB and the drive is 

larger, LBA support is lacking or is not enabled. 

7. Enable LBA mode and try steps 2–5 again. If FDISK reports 

the same or similar size to what the BIOS reports, your drive 

is being translated correctly by the BIOS if your hard disk is 

8.4GB and you are using Windows 

9x/2000/Me/NT, the size that FDISK should report might be 

greater than what the BIOS displays. If FDISK reports only 

8.4GB and the hard disk is larger, see Table 4.5 for solutions. 

Note 


Remember that hard drive manufacturers rate their hard disks in 

decimal MB or GB, and most BIOSs follow the FDISK standard 

for rating drives in binary MB or GB. See the MB, GB, and TB 

translation table (Table 1.2) in Chapter 1 for equivalents. 

9. If you can’t start the computer after installing the new hard 

drive, the BIOS is incapable of handling the drive’s geometry. 

See Table 4.8 for solutions. 

Using FDISK to Determine Compatibility Problems 

Between the Hard Disk and BIOS 

A mismatch between the capacity that FDISK reports for a hard disk 

and what the BIOS reports for the hard disk indicates a problem 

with LBA translation or with support for hard disks above 8.4GB. 

FDISK can also be used to determine when the dangerous “DOS 

wraparound” condition exists, in which a drive prepared with LBA 

translation has the LBA translation turned off. 

I’ve included a mock-up of how the FDISK Display Partition 

Information screen appears. See the discussion of LBA mode earlier 

in this chapter for solutions. In Figure 4.7, FDISK indicates no problems, 

because the values for X (size of hard disk partition) and Y 

(total size of drive) are equal. 

Display Partition Information Current fixed 

disk drive: 1 

Label Mbytes System Usage C: 1 

A PRI DOS

102 


Partition Status Type Volume 

W95US1U 1626 FAT16 100% 

X 

Total disk space is 1626 Mbytes (1 Mbyte = 

1048576 bytes) 

Y 

Press Esc to continue 

X=Size of hard disk partition (drive has already been 

FDISKed) 

Y=Total disk space (as seen by FDISK) 

Use Table 4.5 to determine what the FDISK total disk space figure is 

telling you about your system. 

Table 4.5 FDISK Disk Space Detected as a Guide to Disk Problems 

X Value1 Y Value2 Drive Size Underlying Cause 

>504MB =504MB >504MB Binary Drive was prepared with LBA 

/FDISK (528MB mode enabled, but LBA 

Decimal) mode has been disabled in 

BIOS. 

See “Dangers of Altering 

Translation Settings” earlier 

in this chapter. 

Not listed =504MB >504MB LBA mode not enabled in 

BIOS or not present. 

Not listed 8192MB >8192MB BIOS supports LBA mode, 

(8.38 billion but not Extended Int13h 

bytes) modes. 

1. The X value appears only when a drive has already been FDISKed. 

2. The Y value appears on any drive being viewed through FDISK, whether the FDISK process has 

been completed or not. 

For more information about using FDISK, see the section “Using 

FDISK” later in this chapter. 

Getting LBA and Extended Int13h Support for Your 

System 

If your computer is incapable of detecting the full capacity of your 

hard disk or locks up after you install the hard drive, your BIOS is 

not compatible with your hard drive. Use Table 4.6 to determine 

the causes and solutions that will help you get full capacity from 

your new hard disk with maximum safety.


Table 4.6 Why IDE Drive Is Not Detected at Full Capacity 

Drive Operating 

Symptom Size System Cause Solution 

System locks >2.1GB Any BIOS cannot Upgrade BIOS (see 

up after handle 4,096 Table 4.7). 

installing cylinders or 

new drive. more even 

with LBA 

enabled. 

>32GB Any BIOS cannot Upgrade BIOS (see 

handle capacity 

even with LBA 

enabled. 

Table 4.7). 

Full capacity >504MB– MS-DOS, No LBA mode Upgrade BIOS (see 

not 8.4GB Windows or inadequate Table 4.7). 

available. 9x/NT/2000, LBA support 

OS/2 in BIOS. 

>8.4GB Windows NT Atapi.sys not Update Atapi.sys 

correct version; (included in SP3 or 

BIOS lacks above of NT 4.0) and 

Extended upgrade BIOS if 

Int13h necessary (see 

support, 

required for 

large drives. 

Table 4.7). 

>8.4GB Novell Drivers are Contact Novell for 

NetWare 4.11 needed to drivers; NetWare 5 

support drive will support >8.4GB 

at full drives; upgrade BIOS 

capacity. if necessary. 

>8.4GB IBM OS/2 Patch needed Contact IBM for 

Warp to support patch file; upgrade 

drive at full 

capacity. 

BIOS if necessary. 

>8.4GB Windows 9x Windows 9x Upgrade BIOS (see 

Windows 2000 has Enhanced Table 4.7). 

Windows Me Int13h support 

for drive, but 

BIOS lacks 

support. 

>8.4GB MS-DOS MS-DOS can’t Buy 8.4GB or below; 

use IDE drives update to Windows 

above 8.4GB. 9x; use SCSI drives; 

use big. 

Determining Whether Your System Supports Extended 

Int13h 

Drives that are 8.4GB or larger require Extended Int13h support in 

the BIOS to be accessible at full capacity. This size represents a second 

barrier to drive capacity for MS-DOS, and one that cannot be

104 


overcome without changing to a different type of drive (SCSI) or 

making the move to Windows 9x/2000/Me. 

Even if you have updated versions of operating systems that support 

IDE capacities beyond 8.4GB, your BIOS must also offer this 

support. Table 4.7 describes the differences between how LBA and 

Extended Int13h drive support work. 

Table 4.7 LBA Mode Versus Extended Int13h 

Mode Setting BIOS Drive Capacity Listing 

LBA Must be set in BIOS by Indicates full capacity of drive; 

user or automatically by might or might not indicate 

drive-type detection. translation in BIOS. 

Extended Automatically enabled BIOS configuration might or 

Int13h when LBA mode is might not indicate full capacity 

enabled on systems that 

support Extended Int13h 

functions. 

of drive. 

This support is not “visible” in the BIOS; there is no Enhanced 

Int13h option to enable as there is with LBA mode. 

Also, in some cases, the geometry reported by drives of varying 

sizes doesn’t change either. On a system that supports Extended 

Int13h but doesn’t display the full drive capacity in the BIOS configuration, 

an 8.4GB hard disk will report a geometry to the BIOS 

of 16 heads, 16,383 cylinders, and 63 sectors per track, and a 

20.4GB hard disk reports the same geometry! Support of hard disks 

beyond 8.4GB on some systems breaks the usual rule about the 

BIOS configuration matching the drive’s capacity. 

As with the previously mentioned LBA mode issues, use FDISK to 

determine whether your system supports your greater-than-8.4GB 

IDE hard drive at full capacity. 

Drive Capacity Issues in Microsoft Windows 95 and 98 

Table 4.8 lists the capacity limitations and issues for Windows 95 

and 98. 

Table 4.8 Drive Capacity Issues for Windows 95 and 98 

Windows Drive Capacity 

Version Limitation Fix 

Windows 95 32GB None; upgrade to Windows 98, NT, 

(all releases) 2000, or Me before installing larger hard 

drive. 

See Microsoft online document Q246818 

for details.

Sources for BIOS Upgrades 105 

Table 4.8 Drive Capacity Issues for Windows 95 and 98 Continued 

Windows Drive Capacity 

Version Limitation Fix 

Windows 98 32GB and up Graphical version of ScanDisk lists errors 

(all releases) for all sectors beyond 32GB on some systems 

using Phoenix BIOS with BitShift IDE 

drive translation. 

See Microsoft online document Q243450 

for download (Microsoft Knowledgebase). 

Use command-line ScanDisk as a 

workaround. 

Windows 98 64GB and up Drive works at full capacity, but FDISK 

(all releases) reports capacity as 64GB lower than actual; 

see Microsoft online document Q263044 for 

patch download instructions. 

Windows 98 64GB and up FORMAT run from command line reports 

(all releases) capacity as 64GB lower than actual, but 

FORMAT works correctly; use FORMAT 

option within Windows Explorer as a 

workaround. See Microsoft online document 

Q263045. 

Sources for BIOS Upgrades and 

Alternatives for Large IDE Hard 

Disk Support 

If your BIOS doesn’t support the full capacity of your hard disk, use 

Table 4.9 to choose your best solution. 

Table 4.9 Sources for BIOS and Alternative Support for Large 

Hard Drives 

Solution Benefits Cost Concerns 

Upgrade BIOS. Best all- Free if BIOS Be sure to correctly 

around is Flash type identify your system or 

solution to and is motherboard before 

hard disk supported by installing the upgrade; 

and other motherboard test afterward (see 

support or system Chapter 3 for details). 

issues. maker. 

If BIOS is no See Chapter 3 for 

longer sources and system 

supported by 

MB or 

manufacturer, 

purchase 

upgrade. 

details.

106 


Table 4.9 Sources for BIOS and Alternative Support for Large 

Hard Drives Continued 

Solution Benefits Cost Concerns 

Purchase BIOS May be less $35–$75; Make sure card is 

upgrade card. expensive than can be designed for full capacity 

purchasing combined of your hard disk; many 

BIOS with Y2K early versions had 2.1GB 

replacement date-rollover or 8.4GB limits; requires 

or new support or open ISA or PCI slot. 

motherboard; UDMA 33/66 

fast, easy 

install. 

features. 

Use BIOS You probably Download it Worst choice for large 

replacement received a from your hard disk support 

feature in copy of it hard disk because software drivers 

hard disk with your vendor if and non-standard disk 

installation drive. your drive structures can be altered 

software didn’t come and destroyed very 

supplied with 

drive. 

with a copy. easily. 

After you decide on a strategy for handling the full capacity of your 

hard disk, don’t change it! Don’t use a BIOS replacement option in 

a program such as Disk Manager or EZ-Drive and then decide to 

install a BIOS upgrade (flash, chip, or card). The BIOS support 

won’t be capable of working with your drive because it’s already 

being translated by the software. Make your choice before you finish 

your drive installation. 

Standard and Alternative Jumper 

Settings 

If you decide to use the BIOS replacement software shipped with 

the hard drive instead of downloading or purchasing a BIOS 

upgrade, you might need to use alternative jumper settings on your 

hard disk. An example of these settings as used by some Western 

Digital drives with capacities at 32GB or above is shown in Figure 

4.4. Many other drive makers use similar approaches to deal with 

this problem, as well as with the previous capacity limitation of 

2.5GB seen with older systems. Note that two jumper blocks are 

used; the normal master and slave jumper block plus a second 

jumper block to reduce the reported capacity of the drive. 

The Normal configurations (top) are used for IDE drives installed in 

systems whose BIOSs can handle drives with capacities over 32GB.

Improving Hard Disk Speed 107 

Figure 4.4 Normal (top) and Alternative (bottom) jumpers for Western 

Digital 32GB or larger IDE hard disks with 10-pin jumper blocks. 

The Alternate configurations (bottom)are used to limit the drive’s 

reported capacity to less than 32GB. This configuration is required 

if installing a drive with more than 32GB of capacity causes the 

system to lock up because of BIOS incompatibilities. This condition 

affects many systems with BIOS dates before 6/1/1999. While 

jumpering details vary from brand to brand, two jumper blocks are 

used in almost all cases. 

A drive configured this way requires the use of EZ-Drive, MAXBlast, 

or other drive-manufacturer–supplied disk utility programs to 

access the full capacity of the drive. In some cases, the system 

might need to be shut down at the end of a session rather than 

warm-booted. Check with the drive manufacturer for details on 

using this configuration with Windows NT/2000 or with Linux, 

UNIX, or Novell NetWare. 

Improving Hard Disk Speed 

Although the ATA-2/EIDE standard is best known for establishing 

LBA mode as a means of allowing larger hard drives to be used on 

the IDE interface, a second major benefit of ATA-2/EIDE was 

improving data transfer rates, as shown in Table 4.10. 

Table 4.10 PIO Modes and Transfer Rates 

Cycle Time Transfer Rate 

PIO Mode (ns) (MB/Sec) Specification 

0 600 3.33 ATA 

1 383 5.22 ATA 

2 240 8.33 ATA 

3 180 11.11 ATA-2, EIDE, fast-ATA 

4 120 16.67 ATA-2, EIDE, fast-ATA 

PIO modes 0–2 could be achieved with the original 16-bit motherboard 

or expansion slot-based IDE/ATA host adapters, but PIO

108 


modes 3 and above require a local-bus connection—either VL-Bus, 

PCI card, or (most often) a PCI motherboard connection. 

The first ATA-2/EIDE hard drives introduced in 1994 were capable 

of PIO 3 transfer rates, but newer drives run at PIO 4 transfer rates 

or above. Most recent BIOSs detect the correct PIO mode as well as 

the basic drive geometry and set it for you. On BIOSs that offer a 

PIO mode setting that you must make manually, consult the drive 

vendor for the correct mode. Setting the PIO mode too high will 

cause data corruption. 

Ultra DMA 

The newest hard drives and motherboards support an even faster 

method of data transfer called Ultra DMA, or UDMA for short. See 

Table 4.11 for common Ultra DMA modes. 

Table 4.11 Common Ultra DMA Modes 

Transfer Rate 

UDMA Mode (MB/Sec) Specification 

2 33.33 ATA-4, Ultra-ATA/33 

4 66.67 ATA-5, Ultra-ATA/66 

5 100.00 Ultra-ATA/100 

With both PIO and UDMA modes, the transfer rates listed are maximum 

(burst) transfer rates; sustained rates are much slower. 

Nevertheless, you will want to run your hard disk at the highest PIO 

or UDMA mode it’s capable of. 

UDMA/66 and UDMA/100 Issues 

Most of the greater-than-10GB hard drives now on the market are 

designed to support UDMA/66 (also called Ultra ATA-66) if certain 

requirements are met; many larger drives also support the even faster 

UDMA/1000 standard introduced in the summer of 2000. Table 4.12 

lists the requirements for UDMA/66 and UDMA/100 compliance. 

Table 4.12 Ultra DMA/66 and UDMA/100 Requirements 

Item Features Notes 

Drive Drive must have firmware Some drives automatically sense 

for desired mode. compliance; others require you to 

run a configuration program to 

enable the mode; consult drive 

vendor. 

Motherboard Must have UDMA/66 Check system or MB vendor for 

chipset or UDMA/100 support. compliance; for highest performance, 

you should also install an 

UDMA device driver for operating 

system (see Table 4.13).

Bus-Mastering Chipsets for IDE 109 

Table 4.12 Ultra DMA/66 and UDMA/100 Requirements Continued 

Item Features Notes 

If motherboard can’t run drive at full 

speed, you can add a UDMA/66 or 

UDMA/100 PCI-based IDE interface 

card from sources such as SIIG 

(www.siig.com) or Promise 

Technologies (www.promise.com). 

Cable Cable must be 80-wire Connect blue end of UDMA/66 and 

cable (40 data wires UDMA/100 data cable to motherseparated 

by 40 

ground wires). 

board to ensure proper operation. 

Any system that cannot run the drive at UDMA/66 or UDMA/100 

can use the drive at the system’s maximum speed (UDMA/33, PIO 

4, and so on). 

See Figure 4.5 for a comparison of a standard IDE 40-wire cable 

with an 80-wire cable required for UDMA/66 and UDMA/100 operation. 

Figure 4.5 A standard 40-wire IDE cable (left) compared to an 80-wire 

UDMA/66-100 IDE cable (right). Both cables use the same 40-pin connector. 

The standard cable’s 40 wires give the cable a pronounced ridged appearance 

when compared to the smaller and finer wires in the 80-wire cable. 

Bus-Mastering Chipsets for IDE 

Most late-model Pentium-class and higher motherboards can support 

bus-mastering drivers for their IDE interfaces. The benefits of 

bus-mastering include faster IDE data transfer for CD-ROM, 

CD-R/CD-RW, and hard drives, and lower CPU utilization rates (the 

percentage of total time the CPU spends handling a particular 

task). Table 4.13 lists the major chipsets providing bus-mastering 

features and where to get the driver. Be sure you install the correct 

driver for your chipset.

110 


Even if you enable UDMA/33 or faster UDMA modes in your system 

BIOS, you must install the bus-mastering driver for your hardware 

and operating system to get the maximum benefit out of your 

UDMA-compatible drives. 

Table 4.13 

System 

Bus-Mastering Chipsets by Vendor and Operating 

Vendor Chipsets Driver Source by Operating System 

Intel 430FX (Same driver for all Intel chipsets at left) 

430HX Windows 95 original and OSR1 (95a): 

430VX Download BM-IDE driver from the Intel Web 

440FX site. Windows 95B, 95C (OSR 2.x), Windows 

430TX 

440LX 

440BX 

440EX 

440GX 

440ZX 

440ZX-66 

450NX 

98: Included on Windows CD-ROM. 

Intel 810 Download Ultra ATA Storage Driver (version 

810E 5.x or above) from Intel Web site. Works 

820 with Windows 98, 98SE, Windows 2000, and 

840 Windows NT 4.0. All but Windows 2000 

require use of Chipset Software Installation 

Utility; download from Intel Web site. 

VIA KX133 For Windows 95 (any version) and NT 3.51 

Apollo Pro 133A and higher: Download the drivers from the 

Pro Plus VIA Web site. For Windows 98, 2000, Me: 

Pro 

PM-601 

MPV4 

MVP3 

VP3 

VP2 

VPX 

VP1 

Included on CD-ROM. 

SiS 611 Download the drivers from the SiS Web site. 

85c496 *(For SiS chipsets 5511/5512/5513, 5596/ 

5513**, 5513, 5571, 5581/5582, 5598/5597, 5591/ 

5581/5582, 5595, 600/5595) 

5591, 5571*** **(Separate driver available for use with 

5597/5598, Windows 2000) 

5600 IDE ***(Separate driver available for use with 

Driver* 

SiS530/5595 & 

SiS620/5595 

IDE Driver 

Windows 98) 

ETEQ Various See www.soyo.com.tw to look up models 

motherboard and drivers; download there or from related 

models FTP site.

Table 4.13 Bus-Mastering Chipsets by Vendor and Operating 

System Continued 

Benefits of Manual Drive Typing 111 

Vendor Chipsets Driver Source by Operating System 

PCChips Various See www.pcchips.com to look up IDE 

motherboard drivers by model and operating system 

models (Windows 95, 98, and Windows NT 4.0). 

Ali Aladdin III Windows 95/NT 

(Acer Aladdin IV 

Labs) Windows 

(see note) 

Aladdin V 

Aladdin Pro2 

Linux 

www.acerlabs.com 

95/98/NT 

All Intel chipsets that contain a PIIXn device (PIIX, PIIX3, PIIX4, PIIX4E, and so on) are busmastering 

chipsets. 

Although PCChips chipset names are similar to certain Intel Pentium chipsets (Triton series TX, 

HX, and VX), the drivers listed are strictly for PCChips chipsets, not Intel’s. 

ALi (Acer Labs) recommends checking with motherboard manufacturers’ Web sites first for drivers 

because drivers might be customized for a particular vendor’s products. 

Benefits of Manual Drive Typing 

Even though virtually every BIOS used since the mid-1990s supports 

automatic drive detection (also called drive typing) at startup, a 

couple of benefits to performing this task within the BIOS configuration 

screen do exist: 

• In the event that you need to move the drive to another system, 

you’ll know the drive geometry and translation scheme 

(such as LBA) that was used to access the drive. If the drive is 

moved to another computer, the identical drive geometry 

(cylinder, head, sectors per track) and translation scheme 

must be used in the other computer; otherwise, the data on 

the drive will not be accessible and can be lost. Because 

many systems with autoconfiguration don’t display these settings 

during the startup process, performing the drive-typing 

operation yourself might be the only way to get this information. 

• If you want to remove a drive that is already in use and the 

BIOS displays the drive geometry, write it down! Because the 

IDE interface enables a drive to work with any defined geometry 

that doesn’t exceed the drive’s capacity, the current BIOS 

configuration for any given drive might not be what the 

manufacturer recommends (and what would be detected by 

the BIOS, using the IDE identify drive command). I ran a 

203MB Conner drive successfully for years with an incorrect 

BIOS setting that provided 202MB, because technical information 

about drives in the early days of IDE wasn’t always

112 


easy to get. Drives working with the “wrong” geometry 

should not be “corrected” because this would require a complete 

backup of the drive and resetting the geometry in the 

BIOS, FDISK, FORMAT, and restore. Just label the drive with 

the actual head, cylinder, and sectors per track it uses now. 

Troubleshooting IDE Installation 

In addition to the BIOS capacity and PIO/UDMA mode configuration 

issues, you might run into other problems during an IDE drive 

installation. Use Table 4.14 to determine problems, causes, and 

solutions. 

Table 4.14 Other IDE Drive Installation Problems and Solutions 

Problem Causes Solution 

Drive is not Drive cabling Make sure pin 1 on IDE interface 

recognized by installed and IDE drive are connected to pin 

BIOS, but system incorrectly. 1 (colored edge) of IDE cable; 

will boot from some cables are keyed with a 

floppy (drive plugged hole at pin 20 or with a 

is spinning). “bump” over the middle of the 

cable that corresponds with a 

cutout in the plastic skirt that surrounds 

the cable. 

On non-skirted motherboard IDE 

connectors, make sure pins are 

connected to both rows of the 

cable, without any offsets. 

System display Drive cabling Many systems cannot initialize the 

remains blank reversed; pin 1 video card until the IDE hard drive 

after power on. is connected to is successfully initialized. 

No boot or other pin 39 at either 

activity. drive or interface Use of keyed cables will help to 

connector. eliminate this problem (see previous 

tip). 

Drive not Drive power If a Y-splitter or power extender is 

recognized by cable is not in use, check it for damage or 

BIOS, but system connected or remove it and plug drive directly 

will boot from defective. to power supply; make sure Molex 

floppy (drive power connector is tightly inserted 

is not spinning). into drive; use a Digital Multimeter 

(DMM) to check power leads; 

drive might be defective if power 

checks out okay. 

One or both IDE Drives might Jumper boot drive as master, 

drives on a be jumpered second drive. 

single cable are incorrectly: 

not recognized both 

by system (drives as master or 

are spinning). both as slave.

Table 4.14 Other IDE Drive Installation Problems and Solutions 

Continued 

SCSI 113 

Problem Causes Solution 

One or both IDE Drives might not Reverse master and slave 

drives on a be 100% jumpering; move second drive to 

single cable compliant with ATA other IDE connector and jumper 

are not standards (very both drives accordingly. 

recognized by likely when 

system (drives trying to mix 

are spinning various brands 

and are of IDE drives, 

jumpered especially 

correctly). older ones). 

SCSI 

The small computer system interface (SCSI) is a very flexible and 

high-performance drive and device interface. In addition to supporting 

hard drives, it also can support non-bootable optical and 

tape storage, scanners, and many other device types. 

SCSI Types and Data Transfer Rates 

While many types of SCSI exist, different SCSI types can be mixed 

on the same host adapter. For best results, you should buy a host 

adapter capable of running your fastest devices at their top speeds 

and one that enables various types of devices to run without slowing 

each other down. Use Table 4.15 to learn common SCSI types 

and their characteristics. 

Table 4.15 SCSI Data-Transfer Rates 

Bus Standard Fast Fast-20 Fast-40 Fast-80 Cable 

Width SCSI SCSI1 (Ultra) 2 (Ultra2) 2 (Ultra3) 2 Type 

8-bit 

(narrow) 

5MB/sec 10MB/sec 20MB/sec 40MB/sec 80MB/sec A (50-pin) 

16-bit 10MB/sec 20MB/sec 40MB/sec 80MB/sec 160MB/ P (68-pin) 

(wide) sec3 1. SCSI-2 

2. SCSI-3 

3. Ultra2Wide

114 

Note 


The A cable is the standard 50-pin SCSI cable, whereas the P 

cable is a 68-pin cable designed for 16-bit. Maximum cable 

length is 6 meters (about 20 feet) for standard speed SCSI, and 

only 3 meters (about 10 feet) for Fast/Fast-20/Fast-40 (Ultra) 

SCSI. Ultra2Wide allows cable lengths up to 12 meters (about 

40 feet!). 

Single-Ended Versus Differential 

SCSI 

SCSI is not only a flexible interface, it’s also a multi-platform interface. 

Traditionally, PCs have used single-ended SCSI, whereas other 

platforms use differential SCSI. Because these two types of SCSI are 

not interchangeable, you should never mix them on a host adapter 

designed for single-ended SCSI. Use the markings in Figure 4.6 to 

distinguish between these. 

SCSI SE SCSI LVD 

Single-Ended 

SCSI Devices 

SCSI LVD/SE SCSI DIFF 

Low-Voltage 

Differential/Single-Ended 

Multi-mode SCSI 

Figure 4.6 Single-ended and differential SCSI universal symbols. 

Low-Voltage Differential Devices 

Low-Voltage 

Differential 

SCSI 

High-Voltage 

Differential 

SCSI 

Ultra2Wide SCSI devices, which run at 80MB/sec maximum transfer 

rates, use a modified version of differential SCSI called low-voltage 

differential (LVD). Workstation-oriented cards, such as Adaptec’s 

AHA-2940U2W, enable the use of LVD Ultra2Wide devices and

standard single-ended SCSI devices on the same card. Cards with 

this feature use two buses—one for LVD and one for standard SCSI 

devices. 

Note 

Recognizing SCSI Interface Cables and Connectors 115 

If you do need to use single-ended and differential SCSI devices 

on the same cable, adapters are available that will safely handle 

the connection. Paralan Corporation (4655 Ruffner St., San 

Diego, CA 92111, Tel.: (858) 560-7266; Fax: (858) 560-8929, 

www.paralan.com) offers the SD10B and SD16B adapters. 

Recognizing SCSI Interface Cables 

and Connectors 

Because SCSI is actually a family of standards, each with its own 

cable and connector, matching cables and connectors to the appropriate 

SCSI “family member” is important. Use the following figures 

to determine this information. 

8-Bit SCSI Centronics 50-Pin Connector 

Older, narrow (8-bit) SCSI adapters and external devices use a fullsize 

Centronics type connector that normally has wire latches on 

each side to secure the cable connector. Figure 4.7 shows what the 

low-density, 50-pin SCSI connector looks like. 

25 1 

50 26 

Figure 4.7 Low-density, 50-pin SCSI connector. 

SCSI-2 High-Density Connector 

The SCSI-2 revision added a high-density, 50-position, D-shell connector 

option for the A-cable connectors. This connector now is 

called Alternative 1. Figure 4.8 shows the 50-pin high-density SCSI 

connector. 

25 1 

50 26 

Figure 4.8 High-density, 50-pin SCSI connector.

116 


The Alternative 2 Centronics latch-style connector remains 

unchanged from SCSI-1. 

SCSI-3 68-Pin P Cable 

A new 68-conductor P cable was developed as part of the SCSI-3 

specification. Shielded and unshielded high-density D-shell connectors 

are specified for both the A and P cable. The shielded highdensity 

connectors use a squeeze-to-release latch rather than the 

wire latch used on the Centronics-style connectors. Active termination 

for single-ended buses is specified, providing a high level of 

signal integrity. Figure 4.9 shows the 68-pin high density SCSI connector. 

34 1 

68 35 

Figure 4.9 High-density, 68-pin SCSI connector. 

RAID Array, Hot Swappable 80-Pin Connector 

Drive arrays normally use special SCSI drives with what is called an 

80-pin Alternative-4 connector, which is capable of wide SCSI and 

also includes power signals. Drives with the 80-pin connector are 

normally hot swappable—they can be removed and installed with 

the power on—in drive arrays. The 80-pin Alt-4 connector is shown 

in Figure 4.10. 

Pin 80 

Figure 4.10 80-pin Alt-4 SCSI connector. 

Pin 2 Pin 1 

Apple and some other non-standard implementations from other 

vendors (such as Iomega SCSI Zip drives) used a 25-pin cable and 

connector for SCSI devices. 

They did this by eliminating most of the grounds from the cable, 

which unfortunately resulted in a noisy, error-prone connection. I 

don’t recommend using 25-pin cables and connectors; you should 

avoid them if possible. The connector used in these cases was a 

standard female DB-25 connector, which looks exactly like a PC 

parallel port (printer) connector. Unfortunately, it is possible to


damage equipment by plugging printers into DB-25 SCSI connectors 

or by plugging SCSI devices into DB-25 printer connectors. So, 

if you use this type of SCSI connection, be sure it is marked well, 

because it’s impossible to tell DB-25 SCSI from DB-25 parallel 

printer connectors by looking at them. The DB-25 connector is 

shown in Figure 4.11. 

13 1 

25 14 

Figure 4.11 DB-25 SCSI connector. 

Again, I recommend you avoid making SCSI connections using this 

type of cable or connector. If you must use this type of device, add 

it to the end of the daisy-chain. The 25-wire connector can prevent 

important signals from reaching devices designed to use 50-pin 

connectors, causing them to not be initialized and not function. 

SCSI Drive and Device 

Configuration 

SCSI drives (and other devices) are not too difficult to configure, 

but they are more complicated than IDE drives. The SCSI standard 

controls the way the drives must be set up. You need to set two 

items when you configure a SCSI drive or device: 

• SCSI ID setting (0–7 or 0–15) 

• Terminating resistors 

The number of SCSI IDs available on a host adapter depends on its 

design: 0–7 on SCSI adapters with an 8-bit bus; 0–15 on SCSI 

adapters with a 16-bit bus; two groups of 0–15 on a 16-bit bus with 

a dual-processor host bus adapter. 

SCSI Device ID 

Up to 7 SCSI devices (plus the adapter, for a total of 8) can be used 

on a single narrow SCSI bus (8-bit) or up to 15 devices (plus the 

adapter, for a total of 16) on a wide (16-bit) SCSI bus. Now, dualprocessor, 

16-bit host adapters are available that can operate up to 

30 devices plus the host adapter. In every case, each device must 

have a unique SCSI ID address. The host adapter takes one address, 

so the rest are free for up to 7 SCSI peripherals (or more as defined 

by the host adapter). Most SCSI host adapters are factory-set to ID 7

118 


or 15, which is the highest priority ID. All other devices must have 

unique IDs that do not conflict with one another. Some host 

adapters boot only from a hard disk set to a specific ID. Older 

Adaptec host adapters required the boot hard disk to be ID 0; 

newer ones can boot from any ID. A SCSI device containing multiple 

drives (such as a CD-ROM tower or changer) will have a single 

ID, but each physical drive or logical drive will also be known by a 

logical unit number (LUN). For example, a 5-CD changer is SCSI ID 

#3. Each “virtual drive” or disc position within SCSI ID #3 has a 

LUN of 0–4. So the last “drive” has drive letter J and is also identified 

by Windows as SCSI ID#3, LUN 4. 

Setting the SCSI ID 

The methods for setting the SCSI ID vary with the device. For internal 

drives, the settings are made with jumper blocks. Use Table 4.16 

to set the jumpers. Note that the column to the left is the lowest 

numbered ID jumper, which may be identified as A0 or SCSI ID0, 

depending on the drive vendor. 

Table 4.16 SCSI ID Jumper Settings 

SCSI ID Jumper Settings 

ID# A0 A1 A2 A3 (WD and Quantum Markings) 

ID0 ID1 ID2 ID3 (Seagate Markings) 

00 0 0 0 0 

01 1 0 0 0 

02 0 1 0 0 

03 1 1 0 0 

04 0 0 1 0 

05 1 0 1 0 

06 0 1 1 0 

07 1 1 1 0 

08 0 0 0 1 

09 1 0 0 1 

10 0 1 0 1 

11 1 1 0 1 

12 0 0 1 1 

13 1 0 1 1 

14 0 1 1 1 

15 1 1 1 1 

1 = Jumper On, 0 = Jumper Off


SCAM—Automatic ID Setting 

Some SCSI hard drives and host adapters support SCAM (SCSI 

Configure AutoMagically), which automatically assigns the drive a 

unique SCSI ID number. To use SCAM, both the host adapter and 

drive must support SCAM, and SCAM must be enabled (usually by 

a jumper on the drive). 

SCSI ID Setting for External Devices 

SCSI drives and devices can be used both internally and externally, 

often with the same interface card. For external devices, one of the 

following methods will apply for each device in the SCSI daisychain. 

Use Table 4.14 as a general reference. Typically, the ID setting 

control is at the back of the device, near the SCSI interface cable. 

Depending on the device, the device ID can be set by a rotary dial, a 

push-button control, or a sliding switch. Not all SCSI ID numbers 

are available with every device; many low-cost devices allow a 

choice of only two or three numbers. Regardless of the setting 

method, each internal and external device on a single SCSI daisychain 

of devices must have a unique ID! If you use Adaptec SCSI 

interface cards, use the SCSI Interrogator program before you add a 

new SCSI device to determine which device IDs you have remaining. 

If you are adding a new SCSI device with limited ID choices 

(such as the Iomega Zip 100 SCSI drive), you might need to move 

an existing device to another ID to make room for the new device. 

For high-performance SCSI cards that offer multiple buses, you 

should be able to reuse device numbers 0–7 for each separate bus 

on the card. If you have problems with duplicate ID numbers on 

various buses, the device drivers for either the device or the interface 

card might not be up-to-date. Contact the device and card 

maker for assistance. 

SCSI Termination 

SCSI termination is simple. Termination is required at both ends of 

the bus; there are no exceptions. If the host adapter is at one end of 

the bus, it must have termination enabled. On the other hand, if the 

host adapter is in the middle of the bus—and if both internal and 

external bus links are present—the host adapter must have its termination 

disabled, and the devices at each end of the bus must have 

terminators installed. Unfortunately, the majority of problems that I 

see with SCSI installations are the result of improper termination. 

Terminators can be external or internal (set with a jumper block or 

with switches or sliders). Some devices also terminate themselves 

automatically. 

The pass-through models are required when a device is at the end 

of the bus and only one SCSI connector is available.

120 


SCSI Configuration Troubleshooting 

When you are installing a chain of devices on a single SCSI bus, 

the installation can get complicated very quickly. Here are some 

tips for getting your setup to function quickly and efficiently: 

• Start by adding one device at a time—Rather than 

plugging numerous peripherals into a single SCSI card and 

then trying to configure them at the same time, start by 

installing the host adapter and a single hard disk. Then, you 

can continue installing devices one at a time, checking to 

make sure that everything works before moving on. 

• Keep good documentation—When you add a SCSI peripheral, 

write down the SCSI ID address and any other switch and 

jumper settings, such as SCSI Parity, Terminator Power, and 

Delayed or Remote Start. For the host adapter, record the BIOS 

addresses, IRQ, DMA channel, and I/O Port addresses used by 

the adapter, and any other jumper or configuration settings 

(such as termination) that might be important to know later. 

• Use proper termination—Each end of the bus must be 

terminated, preferably with active or Forced Perfect (FPT) terminators. 

If you are using any Fast SCSI-2 device, you must 

use active terminators rather than the cheaper, passive types. 

Even with standard (slow) SCSI devices, active termination is 

highly recommended. If you have only internal or external 

devices on the bus, the host adapter and last device on the 

chain should be terminated. If you have external and internal 

devices on the chain, you generally will terminate the 

first and last of these devices but not the SCSI host adapter 

(which is in the middle of the bus). 

• Use high-quality shielded SCSI cables—Make sure that 

your cable connectors match your devices. Use high-quality 

shielded cables and observe the SCSI bus-length limitations. 

Use cables designed for SCSI use and, if possible, stick to the 

same brand of cable throughout a single SCSI bus. Various 

brands of cables have different impedance values, which 

sometimes causes problems, especially in long or high-speed 

SCSI implementations. 

• Have the correct driver for your SCSI host adapter 

and for each device—SCSI, unlike IDE, is not controlled 

by your computer’s motherboard BIOS, but by software drivers. 

A SCSI device cannot be used unless the appropriate 

software drivers are installed for it. As with any other 

software-driven peripheral, these drivers are often updated 

periodically. Check for improved drivers and install them as 

needed.

Following these tips will help minimize problems and leave you 

with a trouble-free SCSI installation. 

Use Table 4.17 to help you record SCSI information. Table 4.18 

shows a form I use to record data about my system. You can attach 

this information to the System Template referred to in Chapter 2, 

“System Components and Configuration.” 

Table 4.17 SCSI Device Data Sheet 

Interface I/O Port 

Card 

Interface 

card 

Notes and 

details 

Device 

information 

Include SCSI 

interface 

card and all 

devices below 

IRQ DMA Address 

Cable/ 

Slot Type 

Device ID Device Internal or Connector 

Y/N Name External Type Terminated? 

0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

SCSI Configuration Troubleshooting 121

122 

Table 4.18 Completed SCSI Device Data Sheet 

Interface I/O Port 

Card IRQ DMA Address Slot Type 

Adaptec AHA- 

1535 

10 5 0130h–0133h ISA 

Interface Card Bus-mastering card 

Notes and with internal and 

Details external cable 

connectors; allows 

pass-through so that 

both connectors can 

be used at once 

Device Information 

Include SCSI interface card and all devices 

Device ID Device Internal or 

Cable/ 

Connector 

Y/N Name External Type Terminated? 

0 


1 

2 Epson Expression 636 External 50-pin No 

flatbed scanner with 

transparency adapter 

Centronics 

3 Polaroid SprintScan External 50-pin Yes 

35Plus slide and Centronics 

filmstrip scanner and DB-25 

25-pin 

4 Philips CDD2600 Internal 50-pin ribbon Yes 

5 

CD-Recorder (CD-R) cable 

6 Iomega Zip 100 External DB-25 No 

Zip drive 25-pin 

7 Adaptec AHA-1535 Internal 50-pin ribbon 

SCSI host adapter 

card 

(internal) 

50-pin highdensity 

(external) 

No 

8–15 (No devices) 

Note that both ends of the daisy-chain are terminated and that the 

actual end of the internal daisy-chain is not the AHA-1535 SCSI 

host adapter, but the Philips CDD2600 drive. Also note that some 

SCSI devices support different types of cables. 

Use the worksheet shown in Figure 4.12 to help you plan your SCSI 

cabling and physical layout. Start with the host adapter card. Figure 

4.13 shows a completed worksheet.

SCSI Configuration Troubleshooting 123 

Figure 4.12 SCSI Cabling Worksheet (blank). See Figure 4.13 for a completed 

example. Use data recorded on the SCSI Device Data Sheet shown in 

Table 4.18. 

Figure 4.13 SCSI Cabling Worksheet (completed). This uses data from 

the completed SCSI Device Data Sheet from Table 4.18.

124 

Hard Disk Preparation 

The formatting process for a hard disk drive subsystem has three 

major steps: 

1. Low-level formatting 

2. Partitioning 


3. High-level formatting 

Table 4.19 outlines the steps for preparing a drive for use after 

installation. 

Table 4.19 Comparing the Steps in the Formatting Process 

Process Step When Necessary How Performed 

Low-level IDE and SCSI hard drives 

formatting (LLF) are low-level formatted 

at the factory; reformat 

only to correct errors. 

With SCSI only, to Use factory-supplied LLF or 

configure drive for use diagnostic utilities; use Ontrack 

with a specified host Disk Manager (generic or OEM 

adapter and its driver version); use MicroScope 

software. This is usually version 7 software for IDE. For 

required for Windows SCSI, use the host adapter’s 

3.x/MS-DOS systems, BIOS or software routines (such 

but not for Windows 9x as Adaptec’s EZ-SCSI) if 

systems. necessary. 

Partitioning Always required for both Use operating system utility 

SCSI and IDE hard drives; (FDISK or equivalent) if BIOS 

indicates which portion provides full support for drive 

of the drive will be used capacity; EZ-Drive, Disk 

for each operating system Manager, and similar products 

and how the drive letters can be used for both FDISK and 

will be defined. FORMAT options. 

With SCSI drives under 

Windows 3.x/MS-DOS, hostadapter–specific 

partitioning 

and formatting routines are 

normally used. 

High-level Always required for all Use operating system utility 

formatting drive letters defined by (FORMAT or equivalent); EZ- 

FDISK or partitioning Drive, Disk Manager, and 

utility. similar products can be used for 

both FDISK and FORMAT 

options. 

With SCSI drives under 

Windows 3.x/MS-DOS, hostadapter–specific 

partitioning 

and formatting routines are 

normally used.

Using FDISK 125 

Using FDISK 

FDISK is the partitioning utility used with MS-DOS, Windows 95, 

and above and has equivalents in all other operating systems. In 

most cases with SCSI and all cases with IDE drives, it’s the first software 

program you run after you physically install a hard disk and 

properly detect it in the BIOS. 

FDISK is used to set aside disk space (or an entire physical drive) for 

use by an operating system, and to specify how many and what 

size the logical drives will be within that space. By default, the MS- 

DOS and Windows 9x versions of FDISK prepares a single physical 

drive as a single drive letter (up to the limits listed), but FDISK can 

also be used to create multiple drives. By not preparing all of a hard 

disk’s capacity with FDISK, you can use the remaining room on the 

hard disk for another operating system. 

Drive-Letter Size Limits 

We’ve already considered the physical drive size limits caused by 

BIOS limitations and how to overcome them. Those limits define 

the maximum size a physical hard drive can be. However, depending 

on the version of Windows in use (and with any version of MS- 

DOS), it might be necessary to subdivide a hard drive through the 

use of FDISK to allow its full capacity to be used through the creation 

of multiple logical drive letters. 

The original release of Windows 95 and all versions of MS-DOS 

from DOS 3.3x support FAT16, which allows no more than 65,536 

files per drive and a single drive letter no more than 2.1GB in size. 

Thus, a 6GB hard disk prepared with MS-DOS or the original 

Windows 95 must have at a minimum three drive letters and could 

have more (see Figure 4.14). The primary disk partition (C: on a 

single drive system) can be bootable and contains only a single 

drive letter. An extended partition, which cannot be bootable, contains 

the remainder of the drive letters (called logical DOS drives in 

most versions of FDISK). 

Large Hard Disk Support 

If you use the Windows 95B or above (Win95 OSR 2.x), Windows 

98, or Windows Me versions of FDISK with a hard drive greater 

than 512MB, FDISK offers to enable large hard disk support. 

Choosing to enable large hard disk support provides several benefits: 

• You can use a large hard disk (greater than 2.1GB) as a single 

drive letter; in fact, your drive can be as large as 2TB and still 

be identified by a single drive letter. This is because of the 

FAT-32 file system, which allows for many more files per 

drive than FAT-16.

126 


• Because of the more efficient storage methods of FAT-32, 

your files will use less hard disk space. FAT-32 is not supported 

by Windows NT 4.0 or earlier, but is supported by 

Windows 2000. 

• Note that a FAT-32 drive cannot be directly accessed by older 

versions (pre-OSR 2.x) of Windows 95, Windows 3.1x/MS- 

DOS, or any other operating system. If you occasionally need 

to run older applications that cannot run under Windows 

95B or Windows 98 and you want to store those applications 

on a hard drive, be sure you create a hard drive letter that 

uses FAT-16. This way you can boot your older operating system 

and still access your program files. You can, of course, 

access data on a FAT-32 drive over a network with any computer 

using a compatible network protocol. 

Figure 4.14 Adding a hard drive above 2.1GB in size to an MS-DOS or 

original Windows 95 computer forces the user to create multiple drive letters 

to use the entire drive capacity. The logical DOS drives are referenced like 

any other drive, although they are portions of a single physical hard disk. 

Benefits of Hard Disk Partitioning 

Even though it might seem like a lot of trouble to partition a single 

physical hard disk into multiple drive letters, especially with FAT- 

32, several good reasons exist for both FAT-16 and FAT-32 users to 

partition their hard disks: 

• Multiple partitions can be used to separate the operating 

system, application programs, and data for 

easier backup and greater security—This method for 

dividing a hard disk into C: (Windows and drivers), D: 

(applications), and E: (data) is recommended by PowerQuest

Benefits of Hard Disk Partitioning 127 

(makers of the popular PartitionMagic disk utility), and I’ve 

followed their advice for some time. Some time ago, I lost 

both C: and D: drives to a completely unexpected disk crash, 

but my data, on E:, stayed safe! 

• For FAT-16 operating systems in particular (MS-DOS, 

Windows 95/95a, and others using FAT-16), partitioning 

the drive results in significantly less disk 

space wasted—Because files are actually stored in clusters 

(or allocation units) that are multiples of the 512-byte disk 

sector, a small file must occupy an entire cluster. As Table 

4.20 indicates, the bigger the drive, the greater the space 

wasted. 

Table 4.20 FAT-16 Cluster Sizes 

Drive Size 

Drive Size (Defined by Cluster 

(Defined by FDISK) Drive Maker) Size in Cluster Size 

Binary MB/GB Decimal MB/GB Binary KB in Bytes 

0–127MB1 0–133MB1 2KB 2,048 

128–255MB 134–267MB 4KB 4,096 

256–511MB 268–537MB 8KB 8,192 

512MB–1023MB 

1024MB (1GB)– 

538MB–1073MB 16KB 16,384 

2048MB (2GB) 1074MB–2113MB 32KB 32,768 

1. If you create a partition under 15MB (binary) in size, the operating system actually uses the 

old FAT-12 file system, which results in a cluster size of 8KB! 

FAT-32 Versus FAT-16 Cluster Sizes 

FAT-32 is far more efficient than FAT-16 and is used by virtually 

every recent system with a pre-installed copy of Windows 95 OSR 

2.x (95B/95C),Windows 98, or Windows Me. If you are installing 

an additional hard disk on a system that uses these operating systems, 

use Table 4.21 to determine the relative efficiencies of FAT-16 

versus FAT-32 because you can choose either FAT type for the entire 

new drive or any partitions on it. This chart uses binary 

(FDISK/BIOS) sizes only. 

Table 4.21 FAT-16 Versus FAT-32 

Cluster Size FAT-16 Partition Size FAT-32 Partition Size 

4KB 128MB—255MB 260MB—8GB 

8KB 256MB—511MB 8GB—16GB 

16KB 512MB—1024MB 16GB—32GB 

32KB 1025MB—2048MB 32GB—2TB

128 


Converting FAT-16 Partition to FAT-32 

If your existing hard disk uses FAT-16, you can convert any partition 

on it to FAT-32 if one of the following is true: 

• You have Windows 95B or above (OSR 2.x) and PowerQuest’s 

PartitionMagic v3.x or newer. PartitionMagic has a FAT- 

16–to–FAT-32 converter, which can also reverse the process 

(FAT-32 to FAT-16). 

• You have Windows 98. Windows 98 comes with its own FAT- 

16–to–FAT-32 converter, and it can also use PartitionMagic 

version 4.x or newer. 

NTFS Considerations and Default Cluster Sizes 

New Technology File System (NTFS) is the high-performance file 

system that can be used on Windows NT and Windows 2000 systems. 

It has much more efficient storage by default than FAT-16, 

but it can’t be directly accessed by other versions of Windows or 

MS-DOS. NTFS in Windows 2000 also supports encryption and the 

merging of several physical drives into a single logical folder. 

Use the following guidelines when considering the use of NTFS: 

• Windows 2000 can install a drive of any size recognized by 

the BIOS as a single NTFS volume up to the limits of the BIOS. 

• Windows NT 4.0 must partition a drive of over 4GB into at 

least two drive letters because its boot drive cannot exceed 

4GB. 

• Windows 2000 can be used in a dual-boot environment with 

Windows 98, but if it is installed on the same hard drive partition 

as Windows 98, NTFS cannot be used. 

• NTFS drives require special disk utility programs for defragmentation 

and disk maintenance because their internal 

structure is different from FAT-16 and FAT-32 drives. 

The default cluster sizes for NTFS in Windows 3.51 and above 

(including Windows NT 4.0 and Windows 2000) are listed in 

Table 4.22. 

Table 4.22 Default NTFS Cluster Sizes 

Drive Size NTFS Cluster Size 

512MB or less 512 bytes 

513MB–1024MB(1GB) 1024 bytes (1KB) 

1025MB–2048MB(2GB) 2048 bytes (2KB) 

2049MB and larger 4096 bytes (4KB)

How FDISK and the Operating System Create and Allocate 129 

Note that NTFS drives can be larger than FAT-16 drives and are 

even more efficient than FAT-32 drives. 

The default cluster sizes for FAT-16 drives under Windows NT 4.0 

and Windows 2000 are the same as for Windows 9x and MS-DOS. 

In addition, three more large drive sizes are supported by Windows 

NT 4.0 only (see Table 4.23). 

Table 4.23 

NT 4.0 

Additional FAT-16 Cluster Sizes Supported by Windows 

Drive Capacity Size of FAT (Using FAT-16) 

2048–4096MB (2–4GB) 64KB 

4096–8192MB (4–8GB) 128KB 

8192–16384MB (8–16GB) 256KB 

How FDISK and the Operating 

System Create and Allocate Drive 

Letters 

Two types of partitions can be created with the FDISK in Windows 

9x/Me/2000/NT and MS-DOS: primary and extended. The primary 

partition can be bootable and can occupy all, part, or none of a 

hard disk’s capacity. If you have only one hard disk in a system and 

it’s bootable, at least a portion of that drive’s partition is primary. 

An extended partition is similar to a “pocket” that holds one or 

more logical DOS drives inside it. Table 4.24 shows how FDISK 

identifies these various disk structures as they might be found in a 

typical 13GB hard disk divided into three drives—C:, D:, and E:. 

Table 4.24 FDISK Primary, Extended, and Logical DOS Drives 

Compared (13GB Hard Disk) 

Partition Contained % of Total % of 

Type Size Within Bootable? Disk Space Partition 

Primary 4GB n/a Yes 32.5% 

Drive C: 4GB Primary Yes 32.5% 100% of 

primary 

Extended 9GB n/a No 67.5% 

Logical 4GB Extended No 32.5% 44.4% of 

DOS drive 

D: partition 

extended 

Logical 5GB Extended No 35.0% 55.6% of 

DOS drive extended 

E: partition

130 


With FDISK, the partitions shown earlier must be created in the following 

order: 

1. Create the primary partition to occupy less than 100% of 

disk space at the size you choose up to any limits imposed 

by your operating system. 

2. Create an extended partition to use the remainder of disk 

space unused by the primary partition. 

3. Create one or more logical DOS drives to occupy the 

extended partition. 

4. Before leaving FDISK, make the primary partition (C:) active 

to enable it to boot. 

Assigning Drive Letters with FDISK 

You can use FDISK in many ways, depending on the number of 

hard drives you have in your system and the number of drive letters 

you want to create. 

With a single drive, creating a primary partition (C:) and an 

extended partition with two logical DOS drives within it will result 

in the following drives, as you saw earlier: 

Partition Type Contains Drive Letter(s) 

Primary C: 

Extended D: and E: 

A second drive added to this system should have drive letters that 

follow the E: drive. 

However, you must understand how drive letters are allocated by 

the system to know how to use FDISK correctly in this situation. 

Table 4.25 shows how FDISK assigns drive letters by drive and partition 

type. 

Table 4.25 Drive Letter Allocations by Drive and Partition Type 

Drive Partition Order First Drive Letter 

1st Primary 1st C: 

2nd Primary 2nd D: 

1st Extended 3rd E: 

2nd Extended 4th F: or higher 

How does this affect you when you add another hard drive? If you 

prepare the second hard drive with a primary partition and your

How FDISK and the Operating System Create and Allocate 131 

first hard drive has an extended partition on it, the second hard 

drive will take the primary partition’s D: drive letter. This moves all 

the drive letters in the first hard drive’s extended partition up at 

least one drive letter. 

This example lists a drive with C:, D:, and E: as the drive letters (D: 

and E: were in the extended partition). Table 4.26 indicates what 

happens if a second drive is added with a primary partition on it. 

Table 4.26 Drive Letter Changes Caused by Addition of Second 

Drive with Primary Partition 

Original Drive New Drive Letter(s) 

Partition Letter(s) (First After Adding 

Drive Type Order Drive Only) Second Drive 

1st Primary 1st C: C: 

2nd Primary 2nd — D: 

1st Extended 3rd D:, E: E:, F: 

This principle extends to third and fourth physical drives as well: 

The primary partitions on each drive get their drive letters first, followed 

by logical DOS drives in the extended partitions. 

How can you avoid the problem of changing drive letters? If you’re 

installing an additional hard drive (not a replacement), remember 

that it can’t be a bootable drive. If it can’t be bootable, there’s no 

reason to make it a primary partition. FDISK will enable you to create 

an extended partition using 100% of the space on any drive. 

Table 4.27 shows the same example used in Table 4.25 with the second 

drive installed as an extended partition. 

Table 4.27 Drive Letter Allocations After the Addition of a 

Second Drive with an Extended Partition Only 

Original Drive New Drive Letter(s) 

Partition Letter(s) (First After Adding 

Drive Type Order Drive Only) Second Drive 

1st Primary 1st C: C: 

1st Extended 2nd D:, E: D:, E: 

2nd Extended 3rd — F: 

This operating system behavior also explains why some of the first 

computers with IDE-based (ATAPI) Iomega Zip drives identified the 

Zip drive as D:, with a single 2.5GB or larger hard disk identified as 

C: and E:—the Zip drive was treated as the second hard drive with 

a primary partition.

132 


High-Level (DOS) Format 

The final step in the installation of a hard disk drive is the highlevel 

format. Similar to the partitioning process, the high-level format 

is specific to the file system you’ve chosen to use on the drive. 

On Windows 9x/Me/NT/2000 and DOS systems, the primary function 

of the high-level format is to create a FAT and directory system 

on the disk so the operating system can manage files. You must run 

FDISK before formatting a drive. Each drive letter created by FDISK 

must be formatted before it can be used for data storage. This 

process might be automated with setup programs for some operating 

systems, such as Windows 9x retail versions. In the following 

notes, I provide the steps for a manual drive preparation in which 

you’ll install a full operating system copy later. 

Usually, you perform the high-level format with the FORMAT.COM 

program or the formatting utility in Windows 9x/Me Explorer. 

FORMAT.COM uses the following syntax: 

FORMAT C: /S /V 

This high-level command formats drive C:, writes the hidden operating 

system files in the first part of the partition (/S), and prompts 

for the entry of a volume label (/V) to be stored on the disk at the 

completion of the process. 

The FAT high-level format program performs the following functions 

and procedures: 

1. Scans the disk (read only) for tracks and sectors marked as bad 

during the LLF and notes these tracks as being unreadable. 

2. Returns the drive heads to the first cylinder of the partition 

and at that cylinder (Head 1, Sector 1), it writes a DOS volume 

boot sector. 

3. Writes a FAT at Head 1, Sector 2. Immediately after this FAT, it 

writes a second copy of the FAT. These FATs essentially are 

blank except for bad-cluster marks noting areas of the disk that 

were found to be unreadable during the marked-defect scan. 

4. Writes a blank root directory. 

5. If the /S parameter is specified, copies the system files, 

IO.SYS and MSDOS.SYS (or IBMBIO.COM and 

IBMDOS.COM, depending on which DOS you run) and 

COMMAND.COM to the disk (in that order). 

6. If the /V parameter is specified, prompts the user for a volume 

label, which is written as the fourth file entry in the 

root directory.

Now, the operating system can use the disk for storing and retrieving 

files, and the disk is a bootable disk. 

Note 

Because the high-level format doesn’t overwrite data areas 

beyond the root directory of the hard disk, using programs such 

as Norton Utilities to unformat the hard disk that contains data 

from previous operations is possible—provided no programs or 

data has been copied to the drive after high-level formatting. 

Unformatting can be performed because the data from the 

drive’s previous use is still present. 

If you create an extended partition, the logical DOS drive letters 

located in the extended partition need a simpler FORMAT command 

because system files aren’t necessary—for example, FORMAT 

D:/V for drive D: and FORMAT E:/V for drive E:, and so on. 

Replacing an Existing Drive 

Previous sections discuss installing a single hard drive or adding a 

new hard drive to a system. Although formatting and partitioning a 

new hard disk can be challenging, replacing an existing drive and 

moving your programs and files to it can be much more challenging. 

Drive Migration for MS-DOS Users 

When MS-DOS 6.x was dominant, many users used the following 

straightforward method to transfer the contents of their old hard 

drive to their new hard drive: 

1. The user creates a bootable disk containing FDISK, FORMAT, 

and XCOPY. 

2. The new hard drive is prepared with a primary partition (and 

possibly an extended partition, depending on the user’s 

desires). 

3. The new hard drive is formatted with system files, although 

the operating system identifies it as D:. 

4. The XCOPY command is used to transfer all non-hidden files 

from C:\ (the old hard drive) to D:\, as in the following: 

XCOPY C:\ D:\/S/E 

Replacing an Existing Drive 133 

The XCOPY command also is used as necessary to transfer 

files from any remaining drive letters on the old hard drive 

to the corresponding drive letters on the new drive.

134 

Because the only hidden files such a system would have were probably 

the operating system boot files (already installed) and the 

Windows 3.1 permanent swap file (which could be re-created after 

restarting Windows), this “free” data transfer routine worked well 

for many people. 

After the original drive was removed from the system, the new 

drive would be jumpered as master and assigned C:. You would 

need to run FDISK from a floppy and set the primary partition on 

the new C: drive as Active. Then, exit FDISK and the drive would 

boot. 

Drive Migration for Windows 9x/Me Users 

Windows 9x and Me have complicated the once simple act of data 

transfer to a new system by their frequent use of hidden files and 

folders (such as \Windows\Inf, where Windows hardware drivers 

are stored). The extensive use of hidden files was a major reason for 

a greatly enhanced version of XCOPY, known as XCOPY32, to be 

included in Windows 9x and Me. 

Note 


XCOPY32 is automatically used in place of XCOPY when XCOPY 

is started within a DOS session under Windows. XCOPY32, as 

the name implies, must be run within Windows. 

XCOPY32 for Windows 9x Data Transfer 

Compared to the classic XCOPY, XCOPY32 can copy hidden files; 

preserve file attributes such as system, hidden, read-only, and 

archive; automatically create folders; and is compatible with long 

filenames. Thus, using it to duplicate an existing drive is possible, 

but with these cautions: 

• The XCOPY32 command is much more complex. 

• Errors might occur during the copy process because of 

Windows’ use of temporary files during normal operation, 

but XCOPY32 can be forced to continue. 

This command line calls XCOPY32 and transfers all files and folders 

with their original attributes intact from the original drive (C:) 

to the new drive (D:). This command must be run from an MS-DOS 

session under Windows 9x or Me: 

xcopy32 c:\. d:\/s/c/h/e/r/k

The command switches are explained here: 

• /S—Copies folders beneath the starting folder. 

• /C—Continues to copy after errors. (The Windows swap file 

can’t be copied due to being in use.) 

• /H—Copies hidden and system files. 

• /E—Copies folders, even if empty. 

• /R—Overwrites read-only files. 

• /K—Preserves file attributes. 

Repeat the command with appropriate drive-letter changes for any 

additional drive letters on your old drive. 

After the original drive is removed from the system, the new drive 

needs to be jumpered as master (or single); the operating system 

will assign it C:. You also must run FDISK from a floppy and set the 

primary partition on the new C: drive as Active. Then, exit FDISK, 

and the drive will boot. 

This process can take a long time because of the overhead of running 

an MS-DOS session beneath Windows. 

If your hard disk comes with a disk preparation utility, such as EZ- 

Drive, Data Lifeguard Tools, MAXBlast, Disk Manager, Disc Wizard, 

or others, it might include a fast data transfer utility you can use in 

place of this procedure. I also recommend the PowerQuest utility 

DriveCopy, which uses a special method called SmartSector copying 

to copy hundreds of megabytes of data from the old drive to 

the new drive in just a few minutes. 

Note 

Hard Disk Drive Troubleshooting and Repair 135 

If your hard drive was original equipment in your computer, or if 

you purchased a replacement from bulk stock, you might not 

have received the appropriate installation disk for your drive. 

Check the drive maker’s Web site for a downloadable version. 

Hard Disk Drive Troubleshooting 

and Repair 

Hard disk problems fall into two categories: hard and soft. Hard 

problems are triggered by mechanical problems that cause the drive 

to emit strange grinding or knocking noises (or no noise at all!), 

whereas soft problems are read and write errors that occur in a drive

136 

that sounds normal. Before deciding a hard disk is defective, test it 

on another known-working system. If the problem goes away on 

another system, the drive is not the problem (see Table 4.28). 

Note 


Before using this table, verify that your drive’s BIOS configuration 

is correct. If your system’s LBA or other drive translation settings 

are disabled and your drive needs them, it will appear to 

hang. 

Table 4.28 Hard and Soft Problems and Solutions 

Symptom Cause Solution 

Drive makes banging Stiction (Static friction) If drive hangs, try tapping 

noise on initial power is causing the heads gently on one corner to 

up; can’t boot without to stick to the media free the heads or mount 

restarting the computer because of an aging the drive upside down. 

a couple of times; mechanism and Back up data and replace 

usually found on very lubrication problems drive as soon as possible. 

old (under 100MB) RLL 

or MFM hard disks only; 

these drives use two 

(20-pin and 34-pin) 

data and signal cables. 

internally. 

Drive makes scratching Severe head damage, Replace drive. 

or “boinging” noise probably caused by 

internally; won’t boot. impact (fall or drop). 

Drive spins normally If cable and jumpering Replace logic board or 

but can’t be recognized. okay, probably failed 

logic board. 

replace drive. 

Drive has repetitive If system rebooted or Remind user to shut down 

errors detected by was turned off without computer normally. 

SCANDISK or other proper shutdown, these 

disk testing utility. are temporary files that 

weren’t closed. This does 

not indicate a hardware 

problem. 

If normal shutdown If normal shutdown 

procedure followed, procedure was followed, 

might indicate get manufacturer utility 

marginal disk to detect and remap 

surface. sectors and retest drive 

frequently. If drive doesn’t 

improve, replace as soon 

as possible. 

If replacing the logic assembly does not solve the problem, contact 

the manufacturer or a specialized repair shop that has clean-room 

facilities for hard disk repair.

MS-DOS Command-Line Access to CD-ROM Drives 137 

Optical Drive Interface Types 

Most internal CD-ROM, CD-R, and CD-RW drives are ATAPI-based 

(ATAPI uses the standard IDE interface). Some high-performance 

drives in either internal or external form factors are SCSI-based. 

Physical installation and cabling is the same as for any other IDE 

(ATAPI) or SCSI device, as seen earlier in this chapter. 

Some external drives use parallel-port or USB port connectors. See 

Chapter 7, “Parallel Ports, Printers, Scanners, and Drives,” and 

Chapter 8, “USB and IEEE-1394 Ports and Devices,” for troubleshooting 

and configuration tips for drives using these interface types. 

MS-DOS Command-Line Access to 

CD-ROM Drives for Reloading 

Windows 

CD-ROM drives are normally controlled in Windows 9x and Me by 

32-bit drivers, but these drivers will not work if the operating system 

becomes corrupted or if Windows will only work in Safe mode. In 

those cases, having access to the CD-ROM drive becomes critical to 

enable you to reload the operating system. 

In Windows 98 and Me, the Emergency Disk you can create during 

initial installation or later contains drivers that work for most 

IDE/ATAPI and SCSI-based CD-ROM drives. In addition, the disk 

will try each driver until it finds one that works. 

In Windows 95, the Emergency Disk does not contain drivers for 

the CD-ROM. Follow these general guidelines to create a working 

boot disk with CD-ROM support. This same process will work for 

MS-DOS/Windows 3.1 users. 

The following instructions are for IDE (ATAPI) CD-ROM drives. 

SCSI-based, CD-ROM drives will also require SCSI device drivers for 

the host adapter and devices attached: 

1. Create the Windows 95 Emergency Disk (it’s bootable) from 

the Control Panel’s Add/Remove Programs icon—Windows 

Setup tab. This process destroys all previous contents on the 

disk. 

2. Copy the following files to your bootable disk in the A: drive: 

• MYCDROM.SYS—Use the actual driver name for your 

CD-ROM drive and copy it from the file’s actual location. 

If you don’t have an MS-DOS driver, you can 

download one from the drive’s manufacturer, or 

download an ATAPI driver called AOATAPI.SYS available 

from several Web sites.

138 

• MSCDEX.EXE—Copy from C:\WINDOWS\ 

COMMAND or your CD-ROM drive’s folder; the same 

file for any CD-ROM drive. 

Next, you’ll need to create a CONFIG.SYS file that will load the CD- 

ROM device driver and an AUTOEXEC.BAT that will load the 

MSCDEX.EXE CD-ROM extensions for MS-DOS program. Use a text 

editor, such as the Windows Notepad. 

Contents of CONFIG.SYS: 

• DEVICE=MYCDROM.SYS /D:mscd001 

• Lastdrive=M 

Contents of AUTOEXEC.BAT: 

• MSCDEX.EXE /d:mscd001 /m:10 /L:M 

Note 


Note that the /d: switch refers to the same device name, which 

could be Charlie or Kumquat or anything that matches! A mismatch 

will cause the loading process to fail. 

Check your computer’s BIOS setup and verify that the floppy drive 

is the first bootable device. Then, restart the computer with this 

floppy in drive A: and you should see the CD-ROM driver initialize. 

Next, MSCDEX should assign the CD-ROM the drive letter listed 

after the /L: option (M:). 

If you don’t have a suitable Windows 95 disk with CD-ROM support, 

a popular workaround is to use a Windows 98 or Windows 

Me startup disk because they both contain the CD-ROM drivers 

you need to access your CD for reinstallation of files or the entire 


Troubleshooting Optical Drives 

Failure Reading a CD 

If your CD-ROM drive fails to read a CD, try the following solutions: 

• Check for scratches on the CD’s data surface. 

• Check the drive for dust and dirt; use a cleaning CD.

• Make sure the drive shows up as a working device in System 

Properties. 

• Try a CD that you know works. 

• Restart the computer (the magic cure-all). 


• Remove the drive from the Device Manager in Windows 9x, 

allow the system to redetect the drive, and reinstall drivers (if 

PnP-based system). 

Failure Reading CD-R and CD-RW Disks in a CD-ROM or 

DVD Drive 

If your CD-ROM or DVD drive fails to read CD-R and CD-RW disks, 

try the following solutions: 

• Check compatibility; some very old 1x CD-ROM drives can’t 

read CD-R media. Replace the drive with a newer, faster, 

cheaper model. 

• Many early-model DVD drives can’t read CD-R and CD-RW 

media; check compatibility. 

• CD-ROM drive must be multi-read compatible to read CD- 

RW because of lower reflectivity of media; replace drive. 

• If some CD-Rs but not others can be read, check media color 

combination to see whether some color combinations work 

better than others; change brand of media. 

• Packet-written CD-Rs (from Adaptec DirectCD and backup 

programs) can’t be read on MS-DOS/Windows 3.1 CD-ROM 

drives because of limitations of the operating system. 

IDE/ATAPI CD-ROM Drive Runs Slowly 

If your IDE/ATAPI CD-ROM drive performs poorly, check the following 

items: 

• Check the cache size in the Performance tab of the System 

Properties Control Panel. Select the quad-speed setting 

(largest cache size). 

• Check to see whether the CD-ROM drive is set as the slave to 

your hard disk; move the CD-ROM to the secondary controller 

if possible. 

• Your PIO or UDMA mode might not be set correctly for your 

drive in the BIOS; check the drive specs and use autodetect 

in BIOS for best results.

140 


• Check to see that you are using bus-mastering drivers on 

compatible systems; install the appropriate drivers for the 

motherboard’s chipset and operating system in use. 

• Check to see whether you are using the CD-ROM interface 

on your sound card instead of an IDE connection on the 

motherboard. Move the drive connection to the IDE interface 

on the motherboard and disable the sound card IDE, if 

possible, to free up IRQ and I/O port address ranges. 

• Open the System Properties Control Panel and select the 

Performance tab to see whether the system is using MS-DOS 

Compatibility mode for the CD-ROM drive. If all the IDE 

drives are running in this mode, see www.microsoft.com and 

query on “MS-DOS Compatibility Mode” for a troubleshooter. 

If only the CD-ROM drive is in this mode, see whether you’re 

using CD-ROM drivers in CONFIG.SYS and AUTOEXEC.BAT. 

Remove the lines containing references to the CD-ROM drivers 

(don’t actually delete the lines—REM them), reboot the 

system, and verify that your CD-ROM drive still works and 

that it’s running in 32-bit mode. Some older drives require at 

least the CONFIG.SYS driver to operate. 

Trouble Using Bootable CDs 

Bootable CDs are terrific vehicles for installing a standard software 

image on a series of computers, or as a “bulletproof” method of 

running antivirus software, but they can be tricky to use. 

If you are having problems using a bootable CD, try these possible 

solutions: 

• Check the contents of bootable floppy disk from which you 

copied the boot image during the creation of the bootable 

CD. To access entire contents of a CD-R, a bootable disk must 

contain CD-ROM drivers, AUTOEXEC.BAT, and CONFIG.SYS. 

Test the bootable disk by starting the system with it and seeing 

whether you can access the CD-ROM drive afterward. 

• Use ISO 9660 format. Don’t use the Joliet format because it is 

for long-filename CDs and can’t boot. 

• Check your system’s BIOS for boot compliance and boot 

order; CD-ROM should be listed first. 

• Check the drive for boot compliance. 

• SCSI CD-ROMs need a SCSI card with BIOS and bootable 

capability, as well as special motherboard BIOS settings.


• You must use your mastering software’s Bootable CD option 

to create the bootable CD-ROM from the files on the 

bootable floppy. The bootable disk’s AUTOEXEC.BAT, 

CONFIG.SYS, and basic boot files are stored on a bootable 

CD as files called BOOTIMG.BIN and BOOTCAT.BIN by the 

mastering software’s Bootable CD mastering option.

5 

Floppy, Removable, 

Tape, and Flash 

Memory Storage 

Chapter 5 

Floppy Drives 

A 3 1/2-inch 1.44MB floppy drive, the most common type of 

floppy drive in use today, isn’t very expensive to replace. However, 

when it stops working, you might not need to replace it right away, 

if you have the “inside story.” Figure 5.1 shows an exploded view 

of a typical 3 1/2-inch 1.44MB floppy drive. 

Top 

1 2 

5 

Figure 5.1 A typical 3 1/2-inch floppy disk drive. 

1. 34-pin data cable connector 

2. 4-pin power connector 

3. Head-actuator motor 

4. Worm gear to drive actuator motor 

5. Read-write head (one of two) 

3 

4 

8 

6 

7 

9 

6. Write-protect sensor 

Bottom 

10 

7. Media sensor (720KB or 1.44MB) 

8. Spindle (left) and drive motor (right) 

9. Disk ejector button 

10. Logic board

144 

Chapter 5—Floppy, Removable, Tape, and Flash Storage 

Where Floppy Drives Fail—and Simple Fixes 

I spent several years on the road carrying around disassembled PCs 

for use in computer-troubleshooting classes. Typically, I had more 

floppy-drive failures than about anything else, due to the combination 

of inexperienced students, rough handling by airline baggage 

carousels, and the simple fact that a floppy drive is designed to be 

used within the confines of a computer case. I learned how to fix 

drives the hard way—when the only spare I had wasn’t working, 

either. 

The Drive Cover 

The drive cover acts as a dust cover, which is obviously a good idea 

for a drive that uses exposed, relatively soft flexible magnetic 

media. However, a damaged or bent drive cover can bind the disk 

ejector, preventing it from moving. The drive cover can easily be 

removed and bent back into shape. 

The Stepper Motor 

The stepper motor moves the head actuator across the surface of 

the floppy disk media, reading or writing data (see Figure 5.2). 

Head mount 

Head flex 

cable 

Guide shaft 

Head connector 

Stepper 

motor 

Mounting screw 

Head 

assembly 

Worm 

gear 

Figure 5.2 An expanded view of a stepper motor and head actuator. 

On a 3 1/2-inch drive, the stepper motor is often a worm-gear 

arrangement rather than the band drive that was used on the older 5 

1/4-inch drives. The worm gear is very compact, but can be jammed 

by shock. To free it up, carefully unscrew the stepper motor from the 

rear of the drive frame and move the head actuator back and forth

gently until the worm gear moves freely again. Reassemble the drive 

and test it outside the case by running the data and power cable to it 

before you secure it into its normal position. 

Interface Circuit Boards 

A drive’s interface circuit board (also called logic board) can be damaged 

by shock, static electricity, or a power surge. Usually, it can 

easily be removed from the bottom of the drive and replaced by a 

spare circuit board from an identical drive with a bad read/write 

head or stepper motor. Keep such failures around for spare parts. 

Read/Write Heads 

Because of the contact between the heads and disk, a buildup of 

the magnetic material from the disk eventually forms on the heads. 

The buildup should periodically be cleaned off the heads as part of 

a preventive-maintenance or normal service program. 

The best method for cleaning the heads involves the use of a commercial 

wet-method disk head cleaner and a program that spins the 

cleaning disk and moves the heads around the cleaning media. 

MicroSystems Development (www.msd.com) offers the TestDrive 

floppy drive testing program, which contains such a cleaning utility. 

Depending on the drive use and the amount of contaminants 

(smoke, dust, soot) in the air, you should clean the read/write 

heads on a floppy drive only about once every six months to a 

year. 

Do not use standard 3 1/2-inch floppy head cleaners with LS-120 

SuperDisk floppy drives; although these drives can read and write 

to standard disks as well as the 120MB SuperDisk media, a conventional 

cleaner will damage their special read/write heads. Check 

www.superdisk.com for a SuperDisk-compatible cleaning kit. 

Floppy Drive Hardware Resources 

Whether they are built in or not, all primary floppy controllers use 

a standard set of system resources: 

• IRQ 6 (Interrupt Request) 

• DMA 2 (Direct Memory Address) 

• I/O ports 3F0-3F5, 3F7 (Input/Output) 


These system resources are standardized and generally not changeable. 

This normally does not present a problem because no other 

devices will try to use these resources (which would result in a conflict).

146 


Don’t Use a Floppy Drive While Running a Tape Backup 

About the only circumstance that would cause a hardware conflict 

is the use of a floppy drive while a tape backup is running. While 

most high-capacity tape backup drives today no longer use the 

floppy interface, they still often use DMA 2 for fast data transfers. 

Because DMA transfers are not checked by the CPU or any other 

part of the system, simultaneous use of DMA 2 by a tape backup 

and a floppy drive can easily result in data loss on either or both 

media types. 

Disk Drive Power and Data Connectors 

Two sizes are used for disk drive power connectors. Figure 5.3 

shows the original “Molex” power connector used on 5 1/4-inch 

floppy drives. Most 3 1/2-inch floppy drives and tape backups use a 

smaller connector, but either size normally has the same 4-wire 

pinout shown in the figure. 

4 

(+12V) Yellow 

(Gnd) Black 

(Gnd) Black 

(+5V) Red 

3 

2 

1 

1 2 3 4 

Figure 5.3 A disk drive female power supply cable connector. 

Some 3 1/2-inch tape drives come with an extension cable with 

only two wires: a ground wire (black) and a +5v wire (red), because 

their motors use the same +5v power as the logic board does. 

Figure 5.4 shows a typical 5-connector floppy data cable. Typically, 

the 5 1/4-inch edge connectors are seldom used today, unless a 

3 1/2-inch drive has a pin-to-edge connector adapter attached. 

Table 5.1 compares floppy and hard disk ribbon cables.

Pin 1 (Colored Wire) 

Motherboard Connector 

Pin 34 

3.5" Drive “B” Connector 

Figure 5.4 Standard five-connector floppy interface cable. 


5.25" Drive “B” Connector 

Table 5.1 Comparing Ribbon Cables—Floppy Versus Hard Disk 

Interface 

Type Floppy ST-506 ESDI IDE SCSI 

Cable 34-pin 34-pin 40-pin or 50-pin or 

Width 80-strand 68-pin 

Notes Almost all have Can be straight 80-strand cable 

twist between A: or twisted; twist has 40 pins; 

drive connectors away from pin 1; designed for 

and B: drive obsolete and use with 

connectors; twist seldom seen UDMA/66 

toward pin 1 today; used motherboards 

(colored edge with 20-pin and drives 

of cable) ribbon cable 

Table 5.2 lists the parameters for current and obsolete disk drives 

used on PCs. If you are preparing a drive with FORMAT that is 

smaller than the drive’s capacity, you will need to set the FORMAT 

parameters manually. 

A damaged media descriptor byte will prevent programs from properly 

accessing the disk; however, this problem can be fixed with 

Norton Utilities. 

Table 5.2 Floppy Disk Logical Formatted Parameters 

Current Formats Obsolete Formats 

Disk Size 

(inches) 

3 1/2 3 1/2 3 1/2 5 1/4 5 1/4 5 1/4 5 1/4 51/4 

Disk Capacity 

(KB) 

2,880 1,440 720 1,200 360 320 180 160 

Media 

Descriptor 

Byte 

F0h F0h F9h F9h FDh FFh FCh Feh 

Sides (Heads) 2 2 2 2 2 2 1 1 

“Twist” 

3.5" Drive “A” 

Connector 

5.25" Drive “A” 

Connector

148 


Table 5.2 Floppy Disk Logical Formatted Parameters Continued 

Current Formats Obsolete Formats 

Tracks per 

Side 

80 80 80 80 40 40 40 40 

Sectors per 

Track 

36 18 9 15 9 8 9 8 

Bytes per 

Sector 

512 512 512 512 512 512 512 512 

Sectors per 

Cluster 

2 1 2 1 2 2 1 1 

FAT Length 

(Sectors) 

9 9 3 7 2 1 2 1 

Number of 

FATs 

2 2 2 2 2 2 2 2 

Root Dir. 

Length 

(Sectors) 

15 14 7 14 7 7 4 4 

Maximum Root 

Entries 

240 224 112 224 112 112 64 64 

Total Sectors 

per Disk 

5,760 2,880 1,440 2,400 720 640 360 320 

Total 

Available 

Sectors 

5,726 2,847 1,426 2,371 708 630 351 313 

Total 

Available 

Clusters 

2,863 2,847 713 2,371 354 315 351 313 

Floppy Drive Troubleshooting 

Table 5.3 Floppy Drive Troubleshooting Tips 

Problem Cause Solution 

Dead drive—the Bad power supply Measure the power at the cable with a 

drive does not or power cable. voltmeter; ensure that 12v and 5v are 

spin and the LED 

never comes on. 

available to the drive. 

Drive or controller Check BIOS setup for proper drive type 

not properly and ensure the controller is enabled if 

configured in BIOS built in to the motherboard; if an add-on 

setup. card contains a floppy controller and the 

motherboard also has one, disable one or 

the other. 

Bad data cable. Replace the cable and retest. 

Defective drive. Replace the drive and retest. 

Defective controller. Replace the controller and retest. If the 

controller is built into the motherboard, 

disable it via the BIOS setup, install a cardbased 

controller, and retest, or replace the 

entire motherboard and retest.

Table 5.3 Floppy Drive Troubleshooting Tips Continued 

Problem Cause Solution 

Drive LED remains Data cable is on Reinstall the cable properly and retest. 

on continuously. backward at either 

the drive or 

controller 

connection. 

The data cable Reinstall the cable properly and retest; 

could be offset on 

the connector by 

one or more pins. 

replace cable if this doesn’t work. 

Phantom 

directories—you 

Defective cable. Replace the cable and retest. 

have exchanged Improper drive Older drives must have their DC jumper 

disks in the drive, 

but the system 

configuration. (for Drive Changeline support) enabled. 

still believes the Defective drive or Replace the drive and retest. 

previous disk is 

inserted, and even 

shows directories 

of the previous 

disk. 

interface. 

Note 


Windows users: Windows does not automatically refresh the display 

with File Manager, Explorer, and so on by default. Use the 

F5 key or click Refresh to re-read the disk. 

Common Floppy Drive Error Messages—Causes and 

Solutions 

Table 5.4 Handling Floppy Drive Error Messages 

Error Message Cause Solution 

Invalid Media or You are formatting the Make sure you are using the 

Track Zero Bad, disk and the disk media right type of disk for your drive 

Disk Unusable type does not match and formatting the disk to its 

the format parameters. correct capacity. 

Defective or damaged 

disk. 

Replace the disk and retest. 

Dirty read/write heads. Clean drive, allow heads to dry, 

and retest. 

CRC Error or The data read from the Replace the disk and retest. 

Disk Error 23 disk does not match the Clean the drive heads, allow them 

data that was originally to dry, and retest. Use Norton 

written. (CRC stands for Utilities or SpinRite to recover data 

Cyclic Redundancy Check.) from disk.

150 


Table 5.4 Handling Floppy Drive Error Messages Continued 

Error Message Cause Solution 

General Failure The disk is not formatted Reformat the disk and retest. 

Reading Drive A, or has been formatted for 

Abort, Retry, Fail, a different operating system 

or Disk Error 31 (Macintosh, for example). 

Damaged areas on the Replace the disk and retest. Use 

disk medium. Norton Utilities or SpinRite to 

recover data from disk. 

Disk not seated properly Remove and reinsert in drive. Try 

in drive. holding disk in place with your 

hand. If you can read the data, 

copy it to a reliable disk. 

Access Denied You are trying to write Move the write-protect switch to 

to a write-protected disk allow writing on the disk, or 

or file. remove the read-only file attribute 

from the file(s). File attributes can 

be changed by the ATTRIB command 

or through the file properties 

in Windows. 

Insufficient Disk The disk is filled, or the Check to see if sufficient free space 

Space or Disk Full root directory is filled. is available on the disk for your 

intended operation. Use folders 

on the disk to store files, or change 

to a new disk. 

Bytes in Bad Displayed after FORMAT, Operating system will not use bad 

Sectors CHKDSK, or SCANDISK if sectors, but this is a sign of a 

(greater than 0) allocation units (clusters) marginal disk; reformat or discard 

have been marked bad. and use a new disk with no bad 

sectors. 

Disk Type or You are attempting to Disks can be copied only between 

Drive Type DISKCOPY between two drives using the same disk density 

Incompatible incompatible drive and size. Use COPY or XCOPY unless 

or Bad disk types. you are trying to create an exact 

copy. 

Removable Storage Drives 

For backup or alternative main storage, many users today are deemphasizing 

floppy disks in favor of alternative storage media. 

Table 5.5 describes the varying types of storage media, and Table 

5.6 provides an overview of storage types. Of the drives listed, only 

the LS120/SuperDisk, Sony HiFD, and Caleb it drives are also 

read/write compatible with standard 3 1/2-inch floppy media. 

Drives that use SCSI or IDE (ATAPI) interfaces are installed the same 

way as other SCSI or IDE devices. Refer to Chapter 4, “SCSI and IDE 

Hard Drives and Optical Drives,” for details.

Table 5.5 Quick Reference to Removable Magnetic and Flash Stora 

Media Type Media Brands Mfrs Capacity 

Flash memory SmartMedia, ATA Data Various 2MB–512MB, depend 

Flash, Compact Flash, 

Memory Stick 

on brand and model 

Flexible magnetic disk Clik!, Zip, LS-120 Various 40MB–250MB, depen 

SuperDisk, Sony HiFD, 

Caleb it 

on brand and model 

Hard disk MicroDrive IBM 170MB and 340MB 

Hard disk DataPak Kingston 520MB and 1GB 

High-performance, 

flexible magnetic disk 

Jaz Iomega 1GB and 2GB 

High-performance, 

hard disk cartridge 

Orb Castlewood 2.2GB 

.315'' magnetic Travan and Travan NS Various Up to 10GB1 , depend 

tape cartridge on brand & model 

ADR magnetic ADR 30GB and 50GB OnStream 15GB1 and 25GB1 tape cartridge 

DAT, Exabyte 8MM, Various Various Up to 50GB 1 

AIT magnetic tape 

1. Uncompressed capacity: Tape drives are usually rated at 2:1 compression; multiply uncompres 

ing capacity.

152 


Table 5.6 Removable Drive Specifications (In Order by Capacity) 

Drive Disk/Cartridge Average Data Transfer 

Type Mfr. Capacity/Type Seek Time Rate 

Iomega Clik Parallel 40MB Clik not listed 620KB/sec 

Iomega Zip Parallel 1 100MB Zip 29ms 1.4MB/sec 

Iomega Zip IDE/ATAPI 100MB Zip 29ms 1.4Mb/sec 

Iomega Zip SCSI 1 100MB Zip 29ms 1.4MB/sec 

Iomega Zip USB 100MB Zip 29ms 1.2MB/sec 

Iomega Zip 250 SCSI2 250MB Zip 29ms 2.4MB/sec 

Iomega Zip 250 

Parallel 

250MB Zip 29ms 0.8MB/sec 

2 

Iomega Zip 250 

ATAPI/IDE 

250MB Zip 29ms 2.4MB/sec 

2 

Imation LS-120 IDE 

Internal 

120MB SuperDisk 60ms 1.1MB/sec 

3 

Imation LS-120 

Parallel 

120MB SuperDisk 60ms 750KB/sec 

4 

Imation LS-120 USB5 120MB SuperDisk 60ms 700KB/sec 

Imation LS-120 

PCMCIA 

120MB SuperDisk 70ms 440KB/sec 

Caleb it (UHD144) 6 144MB UHD144 30ms 770KB/sec sustained 

Parallel, PC Card burst 

USB, IDE/ATAPI 

1.16MB/sec 

Sony HiFD7 Parallel 200MB HiFD 49ms 600KB/sec 

Sony HiFD USB 200MB HiFD 49ms 700KB/sec 

Sony HiFD8 1.2MB/ 200MB HiFD 49ms 900KB-sec write 

IDE/ATAPI 3.6MB/sec read 

Iomega Jaz (SCSI) 9 2GB Jaz 12ms 7.35MB/sec 

Castlewood ORB IDE 2.2GB ORB 12ms 12.2MB/sec 

Castlewood ORB SCSI 2.2GB ORB 12ms 12.2MB/sec 

Castlewood ORB 

Parallel 

2.2GB ORB 12ms 2MB/sec 

1. While Iomega rates Zip 100 parallel and SCSI versions as having the same transfer rate, SCSI 

versions are as much as 8x faster in actual use. 

2. Zip 250 drives can also read/write Zip 100 media. 

3. New version; original version maximum transfer rate was 660KB/second. All LS-120 

SuperDisk models can read/write standard 1.44MB/720KB 3.5” floppy media. 

4. New version; original version maximum transfer rate was 290KB/second. 

5. New version; original version maximum transfer rate was 400KB/second. 

6. All Caleb it (UHD144) models can read/write standard 1.44MB/720KB 3.5” floppy media. 

7. Parallel and USB versions of Sony HiFD sold by Sony; all HiFD models can read/write standard 

1.44MB/720KB 3.5” floppy media. 

8. Sold by IBM in its Options by IBM line; can read/write standard 1.44MB/720KB 3.5” floppy 

media. 

9. Jaz 2GB drive can also read/write Jaz 1GB cartridges.

Removable Storage Drives 153 

Sources for “Orphan” Drive Media, Repairs, Drivers, 

and Support 

Several removable-media drives have become “orphans” over the 

last few years. While the best long-term recommendation you can 

make is to copy all readable data off an orphan drive and transfer it 

to industry-standard storage devices, you might need to buy 

replacement drives, media, repairs, or parts to enable your clients to 

complete the move to new storage devices. Use Table 5.7 to help 

you locate these sources. 

Table 5.7 Sources for “Orphan” Drive Parts, Service, and Media 

Parts Media 

Drive Status or Repairs Drivers 

Avatar Shark Mfr out of Weymouth Technologies www.windrivers.com/ 

250 business. (508)735-3513 company.htm (“Dead 

www.weymouthtech.com Boards” section) 

Iomega Alpha Obsolete Comet Enterprises, Inc. Follow links from 

8 inch, Beta products (801)444-3600 www.gocomet.com 

5.25 inch, not supported www.gocomet.com (some are at Iomega’s 

21MB by Iomega. Web site, others on 

floptical, Comet Enterprises’ Web 

LaserSafe site) 

All SyQuest SYQT, Inc. Parts, repairs, drives, media, and drivers are 

products purchased available from the SYQT, Inc. Web site: 

(SparQ, product www.syqt.com. 

EZ-Flyer, and parts 

others) inventory 

from Iomega 

after Iomega 

bought 

Syquest’s 

intellectual 

property in 

1999. 

Emergency Access to Iomega Zip Drive Files in Case of 

Disaster 

Most removable-media drives are optimized for use with Windows 

9x/NT/2000/Me. But in the event that the operating system fails, 

you want to be able to access your files, even if you must boot the 

machine to a command prompt. 

The Iomega Zip drive is the most popular removable-media drive, 

and files stored on the PC version can be accessed from an MS-DOS 

prompt using its real-mode Guest.exe driver, even if the drive was 

originally used with Windows 9x/NT/2000/Me. All long filenames 

and folder names will be displayed using their short (8+3 character) 

MS-DOS alias names.

154 


Because the Iomega parallel-port Zip drive can be used on virtually 

any system, I recommend that organizations using Zip media have 

a parallel-port version, even though it’s slower than other versions. 

Table 5.8 indicates what is needed to access the parallel-port Zip 

drive. You can get the files needed from the IomegaWARE CD-ROM 

supplied with recent versions of the Zip drive, or from 

www.iomega.com. Copy the files in Table 5.8 to a bootable floppy 

disk. 

Table 5.8 Accessing Parallel Port Zip Drives 

Drive Interface File 

Iomega Zip 100, Parallel Set port to EPP (best Guest.exe, guest.ini, Aspippm1.sys, 

Zip 250 choice) or bidirectional Aspippm2.sys, Nibble.ilm, Nibble2.ilm, 

modes, not ECP Guesthlp.txt, Manual.exe 

Parallel-port versions of the SyQuest SparQ and EzFlyer 230 drives 

are also available from SYQT (formerly SyQuest). SYQT’s Web site 

(www.syqt.com) also has drivers available for Windows 95; 

Windows 98/98SE; Windows NT; and Windows 2000 for SparQ, 

EzFlyer 230, and other models. 

Troubleshooting Removable Media Drives 

Table 5.9 Troubleshooting Removable Media Drives 

Drive/Interface Problem Solution 

Any parallel- Can’t detect drive Check for IRQ conflicts; IRQ for parallel 

port model with install port must not be used by sound cards 

program. or other devices; verify that install 

disk has correct drivers. 

Any SCSI Drive not Check SCSI IDs; each SCSI device must 

interface model available. have a unique ID number; check 

termination; verify correct drivers 

installed; ASPI drivers must be installed 

for both SCSI interface and each device 

on interface. 

Iomega Zip— Drive makes Drive might have “click of death” 

any interface “clicking” problem; physically examine media for 

sound; can’t damage; use Iomega Diagnostics to 

access files. check media; download Trouble in 

Paradise (TIP) from Gibson Research 

(www.grc.com) for more thorough 

testing. 

Any drive, Drive letter Under Windows 9x/NT/2000, check 

any interface interferes with drive properties and select an available 

network, CD-ROM, drive letter not used by CD-ROM or 

and so on. network.

Types of Flash Memory Devices 

Several different types of flash memory devices are in common use 

today, and knowing which ones your digital camera is designed to 

use is important. The major types include the following: 

• CompactFlash 

• SmartMedia 

• ATA PC Cards (PCMCIA) 

• Memory Stick 

SmartMedia and CompactFlash cards are available from many manufacturers, 

but Memory Sticks are available only from the originator, 

Sony, as of this writing. 

ATA PC Cards can use flash memory or an actual hard disk. They 

can be read directly by the Type II or Type III PC Card (PCMCIA) 

slots found on most notebook computers. 

CompactFlash, SmartMedia, and Sony Memory Stick flash memory 

devices require the use of a card reader to interface with notebook 

or desktop computers. Card readers can plug in to any of the following: 

• Parallel port 

• USB port 

• PC Card Type II slot 


Most devices that use flash memory storage can be connected via 

serial ports for downloading of images or other data, but this is 

much slower and is not recommended for heavy-duty use. 

Tape Backup Drives and Media 

Common Tape Backup Standards 

Several tape backup standards exist for individual client PC and 

small server tape backup drives: 

• QIC, QIC-Wide, and Travan—Three branches of a large 

and diverse family of low-cost “entry-level” tape backup 

drives, which can handle data up to 20GB@2:1 compression 

• DAT (Digital Audio Tape)—A newer technology than 

QIC and its offshoots, using Digital Data Storage technology 

to store data up to 40GB@2:1 compression

156 

• OnStream’s ADR (Advanced Digital Recording)—The 

newest technology aimed at desktop and small network 

backup needs, featuring capacity up to 50GB@2:1 compression 

Other tape backup standards, such as DLT (Digital Linear Tape) and 

8mm are used primarily with larger network file servers and are 

beyond the scope of this book. 

Travan Tape Drives and Media 

Imation created the Travan family of tape drives to provide a standardized 

development from the crazy-quilt of QIC and QIC-Wide 

MC (minicartridge) tape drives that stemmed from the original 

QIC-40 and QIC-80 drives and their DC-2120 cartridges. Note that 

Travan-1 through Travan NS-8 retain read-only compatibility with 

the QIC-80 cartridge. 

Table 5.10 Travan Family Cartridges and Capacities 

Read/Write 

Travan Cartridge Capacity/2:1 Compatible Read Compatible 

(previous name) Compression with with 

Travan-1 (TR-1) 400MB/800MB QIC-80, 

QW5122 

QIC-40 

Travan-3 (TR-3) 1.6GB/3.2GB TR-2, 

QIC-3020, 

QIC-3010, 

QW-3020XLW, 

QW-3010XLW 

QIC-80, QW-5122, TR-1 

Travan 8GB (Travan 4GB/8GB QIC-3095 QIC-3020, QIC-3010, 

4/TR-4) QIC-80, QW-5122, TR-3, 

TR-1 

Travan NS-81 QIC-80 

4GB/8GB QIC-3020, QIC-3010, 

Travan NS-20 10GB/20GB Travan 8GB, QIC-3095 

1. This cartridge is replacing the Travan 8GB (TR-4); a single cartridge can be used on either NS8 

or TR-4 drives. 

Future developments might include an NS-36 model. 

Note 


Backward compatibility can vary with each drive; consult the 

manufacturer before purchasing any drive to verify backwardcompatibility 

issues.

Proprietary Versions of Travan Technology 

Ironically, since Travan technology was designed to bring an end to 

the QIC MC/QIC-Wide tape “wars”, some drives exist that use proprietary 

versions of the Travan standard. Non-standard sizes 

include 

• 5GB Tecmar/Iomega DittoMax 

• 5GB HP/Colorado 

• 6.6GB AIWA Bolt 

• 7GB Tecmar/Iomega DittoMax 

• 10GB Tecmar DittoMax 

• 14GB HP/Colorado 


The drive manufacturer is the principal supplier of media for some 

of these drives, whereas others are also supported with third-party 

media. Consult the drive manufacturers’ Web sites for details. 

For more information about older QIC and QIC-Wide tape drives 

and cartridges, see Upgrading and Repairing PCs, 12th Edition, 

Chapter 12. 

Getting Extra Capacity with Verbatim QIC-EX Tape 

Media 

Many older model, small-capacity tape backups are still in use on 

older workstations and small networks. The rapid increase in hard 

disk capacity is causing many problems in creating tape backups 

that are as safe as possible. The “1 backup = 1 tape” rule is harder 

to live by when Travan 3 (3.2MB compressed capacity) or smaller 

tape drives are used with 4GB or larger hard drives. 

If you use any of the tape standards shown in Table 5.11, you can 

use the listed Verbatim QIC-Extra cartridges as replacements. Note 

that the same QIC-Extra series cartridge can be interchanged 

between a particular QIC, QIC-Wide, and Travan drive type. This is 

because QIC-EX tapes are the same width as normal QIC cartridges, 

but are much longer. Because some tape backup drives can’t handle 

the extra capacity with their own backup software, some models of 

QIC-EX cartridges come with replacement backup software that will 

use the full capacity.

158 


Table 5.11 QIC-EX Tape Media 

Capacity/ Verbatim Capacity/ 

Original Tape Compressed 2:1 QIC-Extra Compressed 2:1 

QIC-801 normal 

length (DC-2120) 

125MB/250MB DC2120EX 400MB/800MB 

QIC-80 longer 

length (DC-2120XL) 

170MB/340MB DC2120EX 400MB/800MB 

QW5122 210MB/420MB DC2120EX 400MB/800MB 

Travan 1 (TR-1) 400MB/800MB DC2120EX 400MB/800MB 

Travan 1 (TR-1) 400MB/800MB TR-1EX 500MB/1.0GB 

QIC-30202 680MB/1.36GB MC3020EX 1.6GB/3.2GB 

QW-3020 850MB/1.7GB MC3020EX 1.6GB/3.2GB 

Travan 3 (TR-3) 1.6GB/3.2GB MC3020EX 1.6GB/3.2GB 

QIC-30202 680MB/1.36GB TR-3EX 2.2GB/4.4GB 

Travan 3 (TR-3) 

1. Also known as “Ximat” 

2. Also known as “Taumat” 

1.6GB/3.2GB TR-3EX 2.2GB/4.4GB 

General guidelines only are shown in the previous table. Check 

with the drive and backup software vendor to verify compatibility 

and maximum capacity with your drive. A more detailed crossreference 

listing of many popular drive models is available online 

at www.ceservice.com/crossrefverbatim.htm. 

OnStream ADR Tape Drives and Media 

OnStream ADR drives offer both standard drive-backup features 

and the capability to treat the cartridge as a drive letter for faster 

access to data. Since their introduction in 1998, these have become 

very popular for new installations. Unlike Travan drives, though, 

they do not work with any media other than their own ADR cartridges. 

Table 5.12 OnStream ADR Family Specifications 

Drive Model Interface Performance Retail Media Used 

DI30 IDE ATAPI 1–2MB/sec $299 ADR 30GB 

DP30 Parallel .7–1.4MB/sec $399 ADR 30GB 

USB30 USB .85–1.7MB/sec $399 ADR 30GB 

SC30 SCSI internal 2–4MB/sec $499 ADR 30GB 

SC30 SCSI external 2–4MB/sec $599 ADR 30GB 

FW30 IEEE-1394 

(FireWire) 

2–4MB/sec $599 ADR 30GB 

SC50 SCSI internal 2–4MB/sec $699 ADR 50GB or 30GB 

ADR50 Int LVD SCSI internal 4–8MB/sec $799 ADR 50GB or 30GB 

ADR50 Ext LVD SCSI external 4–8MB/sec $949 ADR 50GB or 30GB


Choosing the Best High-Performance Backup 

Technology 

Beyond Travan and ADR, several other high-performance backup 

technologies exist. All these technologies are available in various 

SCSI interface versions and can be purchased as internal or external 

drives. However, these drives are much more expensive than 

Travan or OnStream ADR drives. Additionally, they are more likely 

to be used as network tape backups than as individual PC backups, 

although current 20GB or larger EIDE hard drives are large enough 

to justify use of these drives for backup. 

Unlike the confusing backward-compatibility picture for QICfamily 

drives, the more advanced drives in each family are backward 

compatible with smaller drives. 

Table 5.13 summarizes the performance and other characteristics of 

these tape technologies and compares them to Travan 8GB, 20GB, 

and OnStream ADR. The prices of the tape drives vary tremendously 

depending on which version of SCSI is selected, whether the 

drive is internal or external, and whether a single-tape or tape 

library drive is selected. The approximate price range listed is for 

internal and external, single-cartridge tape drives. 

The following standards are listed in order by native capacity. All 

drive interfaces are SCSI except as noted. 

Table 5.13 High-Performance Tape Backup Standards Compared 

Backup Speed 

Capacity/2:1 (Native/ Drive Price Media 

Drive Type Compressed Compressed) Range Cost 

DAT DDS-2 4GB/8GB .5–1.1MB/sec $500–$800 $9–$13 

Travan 8GB 

and NS8 

4GB/8GB .6–1.2MB/sec $200–$380 $32–$38 

Exabyte 8mm 

(Eliant 820) 

7GB/14GB 1–2MB/sec $1200 $10 

Travan 20GB 

and NS20 

10GB/20GB 1–2MB/sec $340–$470 $35–$42 

DAT DDS-3 12GB/24GB 1.1–2.2MB/sec $700–$1000 $18–$23 

Exabyte 8mm 

(Mammoth-LT) 

14GB/28GB 2–4MB/sec $1200–$1500 $40 

ADR 30GB 15GB/30GB 1–2MB/sec IDE 

2–4MB/sec SCSI 

$299–$599 $40 

DAT DDS-4 20GB/40GB 2–4.8MB/sec $1000–$1500 $35–$40 

Exabyte 8mm 

(Mammoth) 

20GB/40GB 3–6MB/sec $2200–$3000 $65–$70 

AIT-1 25GB/50GB or 

35GB/70GB 

3–6MB/sec $1500–$2000 $75–$100

160 

Table 5.13 High-Performance Tape Backup Standards Compared 

Continued 


Capacity/2:1 

Backup Speed 

(Native/ Drive Price Media 

Drive Type Compressed Compressed) Range Cost 

ADR 50GB 25GB/50GB 2–4MB/sec 

SCSI;4–8MB/sec 

LVD SCSI 

$699–$949 $60 

AIT-2 50GB/100GB 6–12MB/sec $3000–$3200 $110–$120 

DLT 2000 15GB/30GB 1.2–2.5MB/sec $1200–$1300 $30–$50 

DLT 4000 20GB/40GB 1.5–3MB/sec $1300–$1850 $60–$75 

DLT 7000 35GB/70GB 5–10MB/sec $4300–$4700 $70–$90 

Successful Tape Backup and Restore Procedures 

A backup tape might be the only thing separating you from a complete 

loss of data. To ensure that every backup can be restored, follow 

the guidelines shown in Tables 5.14 and 5.15 when you create 

a backup or restore one. 

Table 5.14 Tape Backup Tips 

Tip Benefit Notes 

Perform the Tests DMA channels in Keep a spare blank tape at all times 

confidence test computer for safe data to enable you to perform this test 

during tape transfer; sets default whenever new hardware is installed 

backup software transfer rate for backup. or before running a new backup for 

installation. safety. 

Select the “Full” backup backs up Make a disaster recovery backup 

correct backup contents of system, but and test your ability to restore your 

type. operating system must backup to an empty hard drive. 

be restored first before Use other backup types for 

restoring backup. “Disaster 

Recovery” backup creates 

special boot disks and 

enables entire system 

recovery straight from 

tape to an empty hard 

drive. Other backup types 

are designed primarily for 

data backup. 

periodic backups. 

Choose speed Maximum data 

and safety. compression uses the 

least amount of tape and 

is often about as fast as 

other backup types. Use 

Compare after to ensure 

readability.

Table 5.14 Tape Backup Tips Continued 


Tip Benefit Notes 

Don’t use Tape backups are typically Use actual compression ratio 

multiple tapes rated with 2:1 reported during your initial full 

for a single compression assumed; backup to determine your nominal 

backup. this ratio is seldom achieved. tape size. If your tape drive is a 

Using multiple tapes for Travan 3 or smaller, get extra 

a single backup can cause capacity per tape by using 

loss of data if first tape is Verbatim QIC-EX series tapes (see 

lost, because it contains 

tape catalog. Back up a 

large drive with a small 

tape drive by backing up 

sections. 

Table 5.15). 

Avoid Let the tape backup run Don’t use floppy drives because 

multitasking without interruptions, due floppy DMA 2 is often used during 

during the tape to DMA transfers. Turn off backups. 

backup. screensaver and power 

management. Turn off your 

monitor. 

Table 5.15 Tape Restore Tips 

Tip Benefit 

Restore full backups to an empty Avoids overwriting drive with junk data if 

drive if possible. your backup has failed. 

If your full backup is not a disaster You’ll wait less time before you can install your 

recovery type, install the smallest 

possible operating system image 

first. 

backup software and restore your backup. 

Run the confidence test again Verifies that DMA transfers will be successful; 

before you start the restore this requires a blank tape or one that can be 

process. overwritten, so keep one handy. 

Tape Drive Troubleshooting 

Tape drives can be troublesome to install and operate. Any type of 

removable media is more susceptible to problems or damage, and 

tape is no exception. This section lists some common problems and 

resolutions. After each problem or symptom is a list of troubleshooting 

steps. 

Can’t Detect the Drive 

For parallel-port drives, use the tape backup as the only device on 

the drive and check the IEEE-1284 (EPP or ECP) mode required by 

the drive against the parallel port configuration. 

For USB drives, be sure you’re using Windows 98 or higher and that 

the USB port is enabled in the BIOS; many systems originally 

shipped with Windows 95 have this port disabled.

162 


For IDE drives, ensure that the master/slave jumpers on both drives 

are set properly. 

For SCSI drives, check termination and Device ID #s. 

For external drives of any type, be sure the drive is turned on a few 

seconds before starting the system. If not, you might be able to use 

the Windows 9x/2000/Me Device Manager to “Refresh” the list of 

devices, but if this doesn’t work, you’ll need to restart the computer. 

Backup or Restore Operation Failure 

If your tape drive suffers a backup or restore operation failure, follow 

these steps: 

1. Make sure you are using the correct type of tape cartridge. 

2. Remove and replace the cartridge. 

3. Restart the system. 

4. Retension the tape. 

5. Try a new tape. 

6. Clean the tape heads. 

7. Make sure all cables are securely connected. 

8. Rerun the confidence test that checks data transfer speed 

with a blank tape (this test overwrites any data already on 

the tape). 

Bad Block or Other Tape Media Errors 

To troubleshoot bad block or other types of media errors, follow 

these steps: 

1. Retension the tape. 

2. Clean the heads. 

3. Try a new tape. 

4. Restart the system. 

5. Try initializing the tape. 

6. Perform a Secure Erase on the tape (previous data will no 

longer be retrievable from the tape). 

Note that most minicartridge tapes are preformatted and cannot be 

reformatted by your drive. Do not attempt to bulk erase preformatted 

tapes because this will render the tapes unusable.

System Lockup or System Freezing When Running a Tape 

Backup 

If your system locks up or freezes while running a tape backup, follow 

these steps: 

1. Ensure that your system meets at least the minimum requirements 

for both the tape drive and backup software. 

2. Check for driver or resource (IRQ, DMA, or I/O port address) 

conflicts with your tape drive controller card or interface; 

using the floppy drive while making a floppy or parallel-port 

tape backup is a major cause of DMA conflicts. 

3. Set the CD-ROM to master and the tape drive to slave if both 

are using the same IDE port. 

4. Check the BIOS boot sequence; be sure it is not set to ATAPI 

(tape/CD-ROM) devices if the tape drive is configured as a 

master device or as a slave with no master. 

5. Make sure the hard drive has sufficient free space; most 

backup programs temporarily use hard drive space as a buffer 

for data transfer. 

6. Hard drive problems can cause the backup software to lock 

up. Check your hard disk for errors with SCANDISK or a 

comparable utility. 

7. Check for viruses. 


8. Check for previous tape drive installations; ensure that any 

drivers from previous installations are removed. 

9. Temporarily disable the current VGA driver and test with the 

standard 640×480×16 VGA driver supplied by Microsoft. If 

the problem does not recur, contact your graphics board 

manufacturer for an updated video driver. 

10. Files in some third-party Recycle Bins can cause backup software 

to lock up. Empty the Recycle Bin before attempting a 

backup. 

11. Disable antivirus programs and Advanced Power 

Management. 

12. Try the tape drive on another computer system and different 

operating system, or try swapping the drive, card, and cable 

with known good, working equipment.

164 


Other Tape Drive Problems 

Other issues that might cause problems in general with tape backups 

include 

• Corrupted data or ID information on the tape. 

• Incorrect BIOS (CMOS) settings. 

• Networking problems (outdated network drivers and so on). 

• The tape was made by another tape drive. If the other drive 

can still read the tape, this might indicate a head alignment 

problem or incompatible environment. 

Tape Retensioning 

Retensioning a tape is the process of fast forwarding and then 

rewinding the tape to ensure even tension exists on the tape and 

rollers throughout the entire tape travel. Retensioning is recommended 

as a preventive maintenance operation when using a new 

tape or after an existing tape has been exposed to temperature 

changes or shock (for example, dropping the tape). Retensioning 

also restores the proper tension to the media and removes 

unwanted tight spots that can develop. 

Some general rules for retensioning include the following: 

• Retension any tapes that have not been used for over a 

month or two. 

• Retension tapes if you have errors reading them. 

• Retension any tapes that have been dropped. 

• In some cases, it might be necessary to perform the retension 

operation several times to achieve the proper effect. Most 

tape drive or backup software includes a Retension feature as 

a menu selection

Chapter 6 

Serial Ports and 

Modems 

6 

Understanding Serial Ports 

The asynchronous serial interface was designed as a system-tosystem 

communications port. Asynchronous means that no synchronization 

or clocking signal is present, so characters can be sent 

with any arbitrary time spacing. 

Each character that is sent over a serial connection is framed by a 

standard start-and-stop signal. A single 0 bit, called the start bit, 

precedes each character to tell the receiving system that the next 

eight bits constitute a byte of data. One or two stop bits follow the 

character to signal that the character has been sent. At the receiving 

end of the communication, characters are recognized by the 

start-and-stop signals instead of by the timing of their arrival. 

Serial refers to data that is sent over a single wire, with each bit lining 

up in a series as the bits are sent. This type of communication 

is used over the phone system because this system provides one 

wire for data in each direction. Compared to parallel ports, serial 

ports are very slow, but their signals can be transmitted a greater 

distance. The other wires in the serial port are used to control the 

flow of data to or from the port. 

Serial ports are also referred to as COM ports because they are used 

to communicate between devices. 

Physically, serial ports come in two forms, although through 

adapters or specially-wired cable, they have no problems communicating 

with each other. The following figures show the standard 

9-pin (see Figure 6.1) and 25-pin (see Figure 6.2) serial ports. The 

25-pin serial port has pins sticking out, as opposed to the 25-pin 

parallel port, which has holes for pins.

166 

Chapter 6—Serial Ports and Modems 

External 

Device 

Figure 6.1 AT-style, 9-pin serial port connector specifications. 

Pinouts for Serial Ports 

Carrier Detect 1 

Receive Data 

2 

Transmit Data 

3 

Data Terminal Ready 

4 

Signal Ground 

5 

Data Set Ready 

6 

Request To Send 

7 

Clear To Send 

8 

Ring Indicator 

9 

Tables 6.1, 6.2, and 6.3 show the pinouts of the 9-pin (AT-style), 

25-pin, and 9-pin-to-25-pin serial connectors. 

Table 6.1 9-Pin (AT) Serial Port Connector 

Pin Signal Description I/O 

1 CD Carrier detect In 

2 RD Receive data In 

3 TD Transmit data Out 

4 DTR Data terminal ready Out 

5 SG Signal ground — 

6 DSR Data set ready In 

7 RTS Request to send Out 

8 CTS Clear to send In 

9 RI Ring indicator In 

5 

9 

1 6 

Serial 

Parallel 

Adapter

External 

Device 

Understanding Serial Ports 167 

25-Pin D-Shell connector 

Description Pin 

NC 1 

Transmitted Data 

2 

Received Data 

3 

Request to Send 

4 

Clear to Send 

5 

Data Set Ready 

6 

Signal Ground 

7 

Received Line Signal Detector 

8 

+ Transmit Current Loop Data 

9 

NC 

10 

- Transmit Current Loop Data 

11 

NC 

12 

NC 

13 

NC 

14 

NC 

15 

NC 

16 

NC 

17 

+ Receive Current Loop Data 

18 

NC 

19 

Data Terminal Ready 

20 

NC 

21 

Ring Indicator 

22 

NC 

23 

NC 

24 

- Receive Current Loop Return 

25 

Figure 6.2 Standard 25-pin serial-port connector specifications. 

Table 6.2 25-Pin (PC, XT, and PS/2) Serial Port Connector 


1 — Chassis ground — 

2 TD Transmit data Out 

3 RD Receive data In 

4 RTS Request to send Out 

5 CTS Clear to send In 

6 DSR Data set ready In 

7 SG Signal ground — 

13 

1 

25 

14 

Asynchronous 

Communications 

Adapter 

(RS-232C)

168 

Table 6.2 25-Pin (PC, XT, and PS/2) Serial Port Connector 

Continued 


8 CD Carrier detect In 

9 — +Transmit current loop return Out 

11 — -Transmit current loop data Out 

18 — +Receive current loop data In 

20 DTR Data terminal ready Out 

22 RI Ring indicator In 

25 — -Receive current loop return In 

Table 6.3 9-Pin-to-25-Pin Serial Cable Adapter Connections 

9-Pin 25-Pin Signal 

1 8 CD Carrier detect 

2 3 RD Receive data 

3 2 TD Transmit data 

4 20 DTR Data terminal ready 

5 7 SG Signal ground 

6 6 DSR Data set ready 

7 4 RTS Request to send 

8 5 CTS Clear to send 

9 22 RI Ring indicator 

Note 


Macintosh systems use a similar serial interface, defined as RS- 

422. Most external modems in use today can interface with 

either RS-232 or RS-422, but it is safest to make sure that the 

external modem you get for your PC is designed for a PC, not a 

Macintosh. 

Current Loop Serial Devices and 25-Pin Serial Ports 

Whereas normal RS-232 serial devices can be connected to either a 

9-pin or a 25-pin serial port, and 9-pin devices can be adapted to a 

25-pin port, another type of serial device known as a current loop 

device will work with 25-pin ports only. 

By comparing Figures 6.1 and 6.2, you can see that the currentloop 

pins (9, 11, 18, and 25) have no corresponding pins in the 

9-pin serial port. Thus, if you need to connect current-loop devices

to your computer (primarily devices for data acquisition), you must 

use a 25-pin serial port, not a 9-pin port. Adapters cannot be used 

because the current-loop pins are not present in the 9-pin port. 

UARTs 

The heart of any serial port is the Universal Asynchronous 

Receiver/Transmitter (UART) chip. This chip completely controls the 

process of breaking the native parallel data within the PC into serial 

format and later converting serial data back into the parallel format. 

A few modem models lack a true UART and use the resources of the 

computer and operating system for communications in place of a 

UART. These so-called Winmodems are less expensive than ordinary 

modems, but are slower and not compatible with non-Windows 

operating systems, such as Linux. 

UART Types 

UART chips have been improved many times over the years, and 

it’s important to know which UART your serial port(s) uses, especially 

under the following circumstances: 

• You want to attach a modem to the serial port. 

• You plan to transfer data between machines via the serial port. 

• You want to ensure reliable multitasking while using 

Windows with your modem. 

UARTs 169 

Table 6.4 summarizes the characteristics of the major UART chips 

(and equivalents) found in PCs. For more information about 

UARTs, see Chapter 18 of Upgrading and Repairing PCs, 12th Edition, 

from Que. 

Table 6.4 Overview of UART Chip Types 

Maximum Typical 

UART Type Speed Buffer System Notes 

8250 Up to 9600bps No 8088 Original UART; 

replaced by 

8250B 

8250A Up to 9600bps No 8088 Not recommended 

because 

incompatible 

with 8250 

8250B Up to 9600bps No 8088/286 Debugged 

version of 8250 

16450 Up to 19200 No 386/486bps Minimum UART 

(19.2Kbps) for OS/2

170 

Table 6.4 Overview of UART Chip Types Continued 

Maximum Typical 

UART Type Speed Buffer System Notes 

16550A -> D Up to 16-byte 386/486 First chip suit 

115000bps FIFO Pentium able for multi- 

(115Kbps) tasking; can be 

used as pincompatible 

replacement for 

socketed 16450 

16650 Up to 230000bps 32-byte Specialized Faster throughput 

(230Kbps) I/O cards, than 16650 

ISDN terminal series adapters 


(460Kbps) I/O cards, than 16650, 

ISDN terminal 16650 series 

adapters 


(921.6Kbps) I/O cards, than 16550, 

ISDN terminal 16650, 16750 

adapters 

Note 


The previous specifications reflect maximum speeds available 

with standard I/O card designs; some vendors use a clockmultiplication 

feature that can double the effective speed of 

some UARTs in some I/O card applications. 

Identifying Your System UART 

The minimum desirable UART chip is the 16550A series or above, 

but older systems and inexpensive multi-I/O cards might use the 

bufferless 8250 or 16450 series UARTs instead. Two major methods 

can be used to determine which UARTs you have in a system. 

MS-DOS Method (also for Windows NT) 

Use a diagnostic program such as Microsoft MSD, CheckIt, 

AMIDiag, or others to examine the serial ports. These programs also 

list the IRQ and I/O port addresses in use for each serial port. 

Because ports are virtualized under Windows, the reports from a 

DOS-based utility will not be accurate unless you boot straight to a 

DOS prompt and run the diagnostic from there.

Upgrading the UART Chip 171 

OS/2 Method 

Use the MODE COMx command from the OS/2 prompt to view 

serial port information. Look for an entry called Buffer in the list of 

serial port characteristics. If Buffer is set to Auto, the chip is a true 

16650A or better. However, if Buffer is set to N/A, it’s an older 

16450 chip. 

Windows 9x/2000/Me Method 

Open the Start menu, and then choose Settings, Control Panel. 

Next, double-click Modems and then click the Diagnostics tab. The 

Diagnostics tab shows a list of all COM ports in the system, even if 

they don’t have a modem attached to them. Select the port you 

want to check in the list and click More Info. Windows 95 or 98 

communicates with the port to determine the UART type, and that 

information is listed in the Port Information portion of the More 

Info box. If a modem is attached, additional information about the 

modem is displayed. 

High-Speed Serial Ports (ESP and 

Super ESP) 

Some modem manufacturers have gone a step further in improving 

serial data transfer by introducing Enhanced Serial Ports (ESP) or 

Super High-Speed Serial Ports. These ports enable a 28.8Kbps or 

faster modem to communicate with the computer at data rates up 

to 921.6Kbps. The extra speed on these ports is generated by 

increasing the buffer size. These ports are usually based on a 16550, 

16650, or 16750 UART, and some even include more buffer memory 

on the card. 

Lava Computer Mfg. and Byte Runner Technologies are two of the 

vendors that offer a complete line of high-speed serial port cards; 

some models also include parallel ports. 

Upgrading the UART Chip 

Use Table 6.5 to determine where any UART chip might be located 

and what you would need to do to replace it. 

Table 6.5 Upgrading UARTs 

Device Type UART Location Upgrade Method 

Internal modem Modem chipset Replace modem 

Multi-I/O card Socketed or soldered Replace card; 16550 not pinwith 

8250 chips compatible 

Multi-I/O card Socketed or soldered Remove 16450 if socketed; 

with 16450 chips replace card if soldered

172 


Table 6.5 Upgrading UARTs Continued 

Device Type UART Location Upgrade Method 

Multi-I/O card Equivalent to normal Replace card 

with Super I/O UART inside a highly 

integrated surfacemounted 

chip 

Motherboard- Socketed MB chip Remove and replace 16450 

with based I/O 16550AF if socketed; disable 

serial I/O and install new multi 

I/O card with 16550AF or 

better UART 

Newer systems— See the section “UARTs” Disable serial I/O and install 

UART equivalent 

inside Super I/O 

earlier in this chapter new multi I/O card as above 

Serial Port Configuration 

Each time a character is received by a serial port, it has to get the 

attention of the computer by raising an interrupt request line (IRQ). 

8-bit ISA bus systems have 8 of these lines, and systems with a 

16-bit ISA bus have 16 lines. The 8259 interrupt controller chip 

usually handles these requests for attention. In a standard configuration, 

COM 1 uses IRQ 4, and COM 2 uses IRQ 3. 

When a serial port is installed in a system, it must be configured to 

use specific I/O addresses (called ports) and interrupts. The best plan 

is to follow the existing standards for how these devices should be 

set up. For configuring serial ports in either Windows or Linux, use 

the addresses and interrupts indicated in Table 6.6. 

Table 6.6 Standard Serial I/O Port Addresses and Interrupts 

COM x I/O Ports IRQ Equivalent to Linux2 COM 1 3F8–3FFh IRQ 4 ttys0 

COM 2 2F8–2FFh IRQ 3 ttys1 

COM 3 3E8–3EFh IRQ 4 1 ttys2 

COM 4 2E8–2EFh IRQ 31 ttys3 

1. Although many serial ports can be set up to share IRQ 3 and 4 with COM 1 and COM 2, it is 

not recommended. The best recommendation is setting COM 3 to IRQ 10 and COM 4 to IRQ 

11 (if available). If ports above COM 3 are required, it is recommended that you purchase a 

special multiport serial board. 

2. Linux users must use distributions based on kernel 2.2 or better to enable IRQ sharing. With 

older distributions, use the setserial command (found in the Linux startup) to assign different 

IRQs to devices using ttys2 (COM3) and ttys3 (COM4); this also requires you to configure the 

cards to use those IRQs. For more information about setserial and serial ports under Linux, 

refer to the Linux Serial How-To at www.linuxdoc.org/HOWTO/Serial-HOWTO.html.

Avoiding Conflicts with Serial Ports 

Use Table 6.7 to understand possible conflicts with serial ports and 

avoid them. 

Table 6.7 Troubleshooting Serial Port Conflicts 

Problem Reason Solution 

DOS-based DOS and PC BIOS Disable COM 2 and set new device to 

program can’t support COM 1 use COM 2; use Windows program instead 

find COM 3 or 

4 on modem or 

other device 

and 2 only 

Device using Shared IRQs don’t Relocate IRQ for device to a different port. 

COM 3 or 4 work for ISA If device is external, connect to multiport 

conflicts with devices board. (Windows 95/98/NT/2000 can 

COM 1 and 2 handle up to 128 serial ports!) (see earlier) 

Note 

For modem troubleshooting, see the section “Modems” later in 

this chapter. 

Troubleshooting I/O Ports in Windows 9x and Me 

Windows 9x and Me can tell you whether your ports are functioning. 

First, you need to verify that the required communications 

files are present to support the serial ports in your system: 

1. Verify the file sizes and dates of both COMM.DRV (16-bit 

serial driver) and SERIAL.VXD (32-bit serial driver) in the 

SYSTEM directory, compared to the original versions of these 

files from the Windows CD-ROM. They should be the same 

date or later, not older. 

2. Confirm that the following lines are present in SYSTEM.INI: 

[boot] 

comm.drv=comm.drv 

[386enh] 

device=*vcd 


The SERIAL.VXD driver is not loaded in SYSTEM.INI; instead, it is 

loaded through the Registry. 

If both drivers are present and accounted for, you can determine 

whether a particular serial port’s I/O address and IRQ settings are 

properly defined by following these steps (which also work with 

Windows 2000):

174 


1. Right-click the My Computer icon and select Properties. Or, 

you can open Control Panel and left-click the System icon 

twice. 

Then, click the Device Manager tab, Ports entry, and select a 

specific port (such as COM 1). 

2. Click the Properties button and then click the Resources tab to 

display the current resource settings (IRQ, I/O) for that port. 

3. Check the Conflicting Devices List to see whether the port is 

using resources that conflict with other devices. If the port is 

in conflict with other devices, click the Change Setting button 

and then select a configuration that does not cause 

resource conflicts. You might need to experiment with these 

settings until you find the right one. 

4. If the resource settings cannot be changed, they most likely 

must be changed via the BIOS Setup. Shut down and restart 

the system, enter the BIOS setup, and change the port configurations 

there. 

In addition to the COM 1/COM 3 and COM 2/COM 4 IRQ conflicts 

noted earlier, some video adapters have an automatic address 

conflict with COM 4’s I/O port address (not IRQ). 

You can also use the Modems Diagnostic tab (discussed earlier in 

this chapter) to test a serial port, whether or not a modem is actually 

present. 

Advanced Diagnostics Using Loopback Testing 

One of the most useful types of diagnostic test is the loopback test, 

which can be used to ensure the correct function of the serial port 

and any attached cables. Loopback tests are basically internal (digital) 

or external (analog). You can run internal tests by unplugging 

any cables from the port and executing the test via a diagnostics 

program. 

The external loopback test is more effective. This test requires that 

a special loopback connector or wrap plug be attached to the port 

in question. When the test is run, the port is used to send data out 

to the loopback plug, which routes the data back into the port’s 

receive pins so that the port is transmitting and receiving at the 

same time. A loopback or wrap plug is nothing more than a cable 

that is doubled back on itself. 

Following is a list of the wiring necessary to construct your own 

loopback or wrap plugs. Check with the vendor of your testing 

software to determine which loopback plug design you need to use, 

or purchase pre-built ones from the vendor.

Loopback Plug Pinouts—Serial Ports 

• Standard IBM type 25-Pin Serial (Female DB25S) Loopback 

Connector (Wrap Plug). Connect the following pins: 

1 to 7 

2 to 3 

4 to 5 to 8 

6 to 11 to 20 to 22 

15 to 17 to 23 

18 to 25 

• Norton Utilities (Symantec) 25-Pin Serial (Female DB25S) 

Loopback Connector (Wrap Plug). Connect the following pins: 

2 to 3 

4 to 5 

6 to 8 to 20 to 22 

• Standard IBM type 9-Pin Serial (Female DB9S) Loopback 


1 to 7 to 8 

2 to 3 

4 to 6 to 9 

• Norton Utilities (Symantec) 9-Pin Serial (Female DB9S) 

Loopback Connector (Wrap Plug). Connect the following 

pins: 

2 to 3 

7 to 8 

1 to 4 to 6 to 9 


To make these loopback plugs, you need a connector shell with the 

required pins installed. Then, you must wire wrap or solder wires, 

interconnecting the appropriate pins inside the connector shell as 

specified in the preceding list (see Figure 6.3). 

One advantage of using loopback connectors is that you can plug 

them into the ends of a cable that is included in the test. This can 

verify that both the cable and the port are working properly.

176 


Male and Female, 25-pin 

Parallel loopback connectors 

Figure 6.3 Typical wrap plugs including 25-pin, 9-pin serial, and 25-pin 

parallel versions. 

Modems 

Modems provide a vital communications link between millions of 

small- to medium-sized businesses and homes and the Internet, 

electronic banking, and other services. The following information 

will help you get the most out of your modem. 

Modems and Serial Ports 

External modems connect to existing serial ports and don’t contain 

a UART chip. Most internal modems contain their own serial port 

and do contain a UART chip. 

Any external modem that will be used at speeds of 28Kbps or above 

must be connected to a 16550A-type UART or better to run at top 

speeds. For best results with external ISDN terminal adapters, use 

serial ports equipped with 16750 or 16950 UARTs because they support 

maximum speeds in excess of 460Kbps. 

Modem Modulation Standards 

Modems are frequently identified by their protocols. Use Table 6.8 

to determine the speed and other characteristics of a particular protocol. 

Most modems support multiple protocols. 

Table 6.8 Modem Modulation Standards and Transmission Rates 

Maximum Transmission 

Protocol Rate (bps) Duplex Mode 

Bell 103 300bps Full 

CCITT V.21 300bps Full 

Bell 212A 1200bps Full 

ITU V.22 1200bps Half 

ITU V.22bis 2400bps Full 

ITU V.23 1,200/75bps Pseudo-Full 

ITU V.29 9,600bps Half 

ITU V.32 9,600bps Full 

9-pin Serial 

loopback connectors

Table 6.8 Modem Modulation Standards and Transmission Rates 

Continued 

Maximum Transmission 

Protocol Rate (bps) Duplex Mode 

ITU V.32bis 14,400bps (14.4Kbps) Full 

ITU V.32fast 28,800bps (28.8Kbps) Full 

ITU V.34 28,800bps (28.8Kbps) Full 

ITU V.34bis 33,600bps (33.6Kbps) Full 

ITU V.90 56,000bps (56Kbps) 1 Full 

1. While the ITU V.90 (successor to the proprietary 56Kflex and X2 standards) allows for this 

speed of transmission, the U.S. FCC (Federal Communications Commission) allows only 

53,000bps (53Kbps) at this time. 

56Kbps Standards 

Virtually every modem sold today corresponds to one or more of 

the so-called 56Kbps standards for faster downloading from an 

Internet service provider (ISP). Uploading to a remote computer 

must run at the slower V.34bis speeds. 

Table 6.9 lists the original and final 56Kbps standards. 

Modems 177 

Table 6.9 56Kbps Modem Standards 

Modem Chipsets Supported 

Standard (Major Brand Example) Notes 

x2 Texas Instruments First 56Kbps standard in use; 

US Robotics not compatible with K56flex. 

K56flex Rockwell Second 56Kbps standard in 

Hayes, Zoom use; not compatible with x2. 

V.90 All 56Kbps modems Official ITU standard has replaced 

with updated firmware previous proprietary standards 

listed previously. 

V.92 New ITU standard Will allow higher upload speed (to 

44Kbps), quicker access, and callwaiting 

compatibility. Look for 

products in late 2000 or early 

2001. Might require new chipsets. 

Because 56Kbps was originally a proprietary standard that was 

chipset dependent, many early adopters have had problems getting 

high-speed access as more and more ISPs have switched their x2- or 

K56flex-specific modem pools to V.90. Table 6.10 provides guidelines 

for upgrading your non-V.90 modem to the V.90 standard.

178 


Table 6.10 Upgrade Options to V.90 

Original Modem Firmware in 

Model Modem Upgrade Method 

x2 or K56flex Flash-upgradable Check manufacturer’s Web site for 

download to upgrade firmware. 

x2 or K56flex Not upgradable Check manufacturer’s Web site for 

details about a physical modem 

swap; might cost money. 

V.34bis or earlier Any A firmware download or physical 

modem swap will be involved; will 

cost money. 

Hayes, Practical Any Contact Modem Express at 

Peripherals, and 612-553-2075 or on the Web at 

Cardinal Technologies www.hayes.com for upgrades and 

(all defunct) drivers (costs and availability will vary 

by brand and model). 

Hayes-brand modems produced after 

June 11, 1999 are products of Zoom 

Telephonics, and are supported by 

Zoom’s Hayes division. Check 

www.hayesmicro.com for details. 

Upgrading from x2 or K56flex to V.90 with Flash 

Upgrades 

The flash upgrades to V.90 work like a BIOS upgrade for a PC: You 

download the appropriate software from the modem vendor, run 

the flash software, wait a few minutes, and your modem is ready to 

dial in to V.90-based ISPs at top speeds. One major problem is what 

happens inside the modem to the existing firmware: 

• X2 Modems to V.90—x2 and V.90 firmware can coexist in 

modem. 

• K56flex to V.90—Most K56flex modems don’t have room 

for both sets of firmware, so the V.90 firmware replaces the 

K56flex. The lack of a fallback standard has caused problems 

for some users of V.90 modems that were upgraded from 

K56flex models. Table 6.11 will help you find a solution if 

your V.90 connections aren’t reliable. 

Table 6.11 Troubleshooting the V.90 (ex-K56flex) Modems 

Problem Solution Method 

Can’t get Download and If you’re having problems making the 

reliable install the latest connection, dial in with your modem 

connection firmware revisions on a 33.6Kbps line, or pretend that 

with V.90. from the vendor’s your modem is an older model by 

Web site, even installing it as a 33.6Kbps model from 

if you have a 

brand new modem. 

the same vendor.

Table 6.11 Troubleshooting the V.90 (ex-K56flex) Modems 

Continued 

Problem Solution Method 

Your ISP If your modem is a The modem needs to have a 2MB 

supports both so-called “Dualmode” ROM chip to have sufficient room for 

V.90 and K56flex, modem, install both firmware types. 

and you’d like both K56flex and 

a choice. V.90 firmware. 

If your modem won’t 

permit both firmware 

types, download both 

V.90 and K56flex firmware, 

try both, and see 

which one works 

better. 

You’re not sure If your vendor has 

the latest several versions of 

firmware upgrade firmware available for 

was really an download, try some of 

improvement. the earlier versions, as 

well as the latest version. 

An earlier version might 

actually work better 

for you. 

Your modem is a Download the country- Check the Web site for your country; 

non-U.S./Canada specific upgrade for contact tech support if your country 

model. your modem. isn’t listed. 

The firmware Make sure you are 

upgrade was using a V.90 dial-up 

installed, and 

the modem only 

number. 

works at 33.6Kbps Make sure you downor 

less. loaded updated INF files 

or other drivers for your 


Note 

Modems 179 

The problems with moving from K56flex to V.90 do not apply to 

users who have updated their V.34/V.34bis modems directly to 

the V.90 standard, whether by a downloadable firmware update 

or physical modem or chip swap. Even if your V.34/V.34bis 

modem was made by a company that later made K56flex 

modems, you don’t need to worry about this unless you updated 

to K56flex before going to V.90. Then, the troubleshooting advice 

given earlier applies to you as well.

180 


External Versus Internal Modems 

Both external and internal modems are available for desktop systems. 

Table 6.12 helps you determine which type is better suited to 

your needs. 

Table 6.12 External Versus Internal Modems 

Features External Internal 

Built-in 16550 No (uses computer’s Yes (if 14.4Kbps or faster). 

UART or higher serial port UART or 

can use USB). 

Price 

comparison 

Higher. Lower. 

Extras to RS-232 Modem Interface Nothing. 

buy cable or USB cable. 

Ease of moving Easy—unplug the cables Difficult—must open case and 

to another and go! (USB modems remove card, open other PC’s case 

computer require a functioning 

USB port on the other 

computer and 

Windows 98, 2000, 

or Me. 

and insert card. 

1) 

Power supply Plugs into wall 

(brick type). 

None—powered by host PC. 

Reset if Turn modem off, and Restart computer. 

modem hangs then on again. 

Monitoring Easy—External Difficult—unless your communication 

operation signal lights. software simulates the signal lights. 

Interface type Almost always via the Traditionally ISA, but many models 

RS-232 port although, now available in PCI, which should 

USB modems are now work better in new machines, allow 

on the market. Parallel- mapping of COM 3 and 4 away from 

port modems were COM 1 and 2 to avoid IRQ sharing, 

made a few years ago, and will be usable in machines of the 

but never proved. future that will lack ISA slots. 

Popular Portable computers use PC Card 

modems in either dedicated or 

combo card types. 

1. Although late versions of Windows 95 OSR 2.x have USB support, many USB devices actually 

require Windows 98 or better. Use Windows 98, 2000, or Me to achieve more reliable support 

for USB devices. 

Modem Troubleshooting 

Table 6.13 will help you troubleshoot modem problems and get 

you back online.

Table 6.13 Modem Troubleshooting (All Types) 

Modems 181 

Modem Type Problem Solution 

Any Modem fails to dial. Check line and phone jacks on modem. 

Line jack—modem to telco service. 

Phone jack—modem to telephone 

receiver. 

If you’ve reversed these cables, you’ll 

get no dial tone. 

Check the cable for cuts or breaks. If 

the cable looks bad, replace it. 

Make sure your modem has been properly 

configured by your OS. With 

Windows 9x, use the Modems icon in 

Control Panel to view and test your 

modem configuration. From the 

General tab, click the Diagnostics tab, 

click your modem on the serial port it’s 

installed on, and then click More Info. 

This sends test signals to your modem. 

A properly working modem responds 

with information about the port and 

the modem. 

External Modem fails to dial. Make sure the RS-232 modem cable is 

running from the modem to a working 

serial port on your computer and that 

it is switched on. Signal lights on the 

front of the modem can be used to 

determine if the modem is on and if it 

is responding to dialing commands. 

Make sure a USB modem is plugged 

tightly into a USB port. If it is connected 

to an external hub, verify that 

the hub is connected to your system. 

PCMCIA/PCCard Modem fails to dial. Make sure it is fully plugged into the 

PCMCIA/PC Card slot. With Windows 

9x/Me, you should see a small 

PCMCIA/PC card icon on the toolbar. 

Double-click it to view the cards that 

are currently connected. If your 

modem is properly attached, it should 

be visible. Otherwise, remove it, reinsert 

it into the PCMCIA/PC card slot, 

and see if the computer detects it. 

Check dongle used to attach modem 

PCMCIA/PC card modems to jack; 

carry a spare. If your dongle doesn’t 

have a connector to a standard phone 

line, use a line coupler to attach the 

short dongle cable to a longer standard 

RJ-11 cable for easier use. Carry at least 

a 10 RJ-11 phone cable with you for 

easier use in hotel rooms.

182 


Table 6.13 Modem Troubleshooting (All Types) Continued 

Modem Type Problem Solution 

Any Couldn’t Open Port Modem might be in use already, or IRQ 

error message. I/O port–address conflict. Use Device 

Manager to check settings, and reinstall 

drivers. 

System can’t dial Never use a wall jack unless it is clearly 

from wall jack. marked as a “data jack” or you check 

with the staff. A digital phone system’s 

jack looks identical to the safe analog 

jack your modem is made for, but its 

higher voltage will fry your phone. You 

can get phone-line voltage testers from 

sources such as http:// 

warrior.com. If your hotel telephone 

has a data jack built-in, use it. Some 

hotels now offer built-in Ethernet in 

some rooms, so carry your NIC with 

you as well for faster Web access. 

Internal System locks up Modem trying to share a non-sharable 

when trying to IRQ with another port, probably a 

boot up or dial mouse. Move a serial mouse that uses 

modem. the same IRQ as the modem to a different 

COM port with a different IRQ 

(from COM 1/IRQ 4 to COM 2/IRQ 3), 

or use a PS/2 mouse (IRQ 12). If your 

Pentium-class system lacks a visible 

PS/2 port, check with your system vendor 

for the (optional) header cable you 

need. 

Disable your system’s COM 2; set the 

modem to COM 2 using IRQ 3. 

External Computer can’t Check cable type. 

detect modem. Must be RS-232 modem (not null 

modem or straight-through) cable (see 

the following pinouts). 

Check power switch and supply. 

COM port might not be working. 

Check BIOS and enable COM port; test 

port with CheckIt, Windows 

9x/2000/ME Modem diagnostics, others; 

use loopback plug with CheckIt, 

AMIDiag, Norton, and so on for most 

thorough check. 

USB Computer can’t 

Check for IRQ conflicts. 

Check USB ports; enable if necessary. 

detect modem. Check USB cables and hubs.

Using Your Modem Sound to Diagnose Your V.90 Modem 

Connection 

If you listen to your modem when it makes a connection, you may 

have realized that various types of modems make a distinctive connection 

sound, and that different connection speeds also make distinctive 

sounds. 

The three types of 56Kbps modems (K56flex, X2, and V.90) have 

distinctly different “handshakes” of tones, buzzes, and warbles as 

they negotiate speeds with the ISP’s modem. Learning what your 

modem sounds like when it makes a 56Kbps connection and when 

it settles for a V.34-speed connection can help you determine when 

you should hang up and try to connect at a faster speed. 

The “56K=v.unreliable” Web site’s troubleshooting section has a 

number of sound samples of various modems you can play back 

with Real Audio: 

http://www.808hi.com/56k/trouble3.htm 

Compare these sound samples to your own modem; make sure you 

adjust the speaker volume for your modem so you can hear it during 

the call. 

Regardless of the modem, two handshake sounds indicate that your 

modem tried to connect at its 56Kbps mode, but failed and had to 

settle for the v.34 speed of 33.6Kbps or less. 

Support for “Brand X” Modems 

Many computer users today didn’t install their modems, or even 

purchase them as a separate unit. Their modems came “bundled” 

inside the computer, and often have a bare-bones manual that 

makes no mention of the modem’s origin or where to get help. 

Getting V.90 firmware, drivers, or even jumper settings for OEM 

modems like this can be difficult. 

One of the best Web sites for getting help when you don’t know 

where to start is www.windrivers.com, which features a modem identification 

page with the following features: 

• FCC ID: Enter the FCC ID number attached to the modem to 

determine who made it 

• Lookup by chipset manufacturer 

• Modem throughput tests 

• Links to major modem manufacturers 

Modems 183

184 


Pinouts for External Modem Cable (9-Pin at PC) 

For most external modems, you need an RS-232 modem cable, 

which will have a 9-pin connector on one end and a 25-pin connector 

on the other end. Because RS-232 is a flexible standard 

encompassing many different pinouts, be sure the cable is constructed 

according to the following diagram: 

1. PC (with 9-pin COM port - male) 

Modem (25-pin port - female) 

3 TX data 2 

2 RX data 3 

7 RTS 4 

8 CTS 5 

6 DSR 6 

5 SIG GND 7 

1 CXR 8 

4 DTR 20 

9 RI 22 

2. If you purchase an RS-232 modem cable pre-built at a store, 

you’ll have a cable that works with your PC and your 

modem. However, you can use the preceding chart to build 

your own cable or, by using a cable tester, determine whether 

an existing RS-232 cable in your office is actually made for 

modems or some other device. 

Win98SE, Windows 2000, Windows 

Me, and ICS 

Windows 98 Second Edition, Windows 2000 Professional, and the 

new Windows Millennium Edition (Windows Me) all feature a 

built-in gateway program called ICS (Internet Connection Sharing), 

which allows users to share a single dial-up, ISDN, cable modem, or 

xDSL connection. Win98SE, Windows Millennium Edition, and 

Windows 2000 Professional can be purchased as an upgrade to 

older versions of Windows, and users of the original version of 

Windows 98 can purchase a CD-ROM from Microsoft that will 

upgrade the original version to the Second Edition. 

Because ICS is a gateway and clients use TCP/IP networking to use 

the gateway, only the gateway computer needs to use Win98SE,

Windows 2000, or Windows Me. Any computer using TCP/IP with 

the option to set up a gateway can be used as a client, including 

computers using older versions of Windows 9x and other operating 

systems. 

Requirements for ICS 

ICS requires a NIC (Network Interface Card) to be installed in the 

host computer and a network connection to each guest computer 

to share the host’s Internet connection. 

If the Internet connection is made through a NIC (as is the case 

with xDSL or two-way cable modem connections), two NICs are 

required: one for the Internet connection and one for sharing the 

connection. 

ICS will not work with one-way cable modems or with DirecPC 

because these devices use a separate connection for downloading 

and uploading. 

Overview of the Configuration Process 

The configuration process has two parts: 

• Installing ICS on the gateway computer 

• Configuring the clients to use the ICS gateway to reach the 

Internet 

Configuring ICS on the Gateway Computer with Windows 

98SE or Windows Me 

If ICS was not installed when Windows was installed, install it by 

choosing Start, Settings, Add/Remove Programs, Windows Setup. 

Select ICS from the Internet Tools category (Win98 Second Edition) 

or from the Communications category (WinMe). 

Note 


Windows Me will start the Home Networking Wizard as soon as 

you install ICS; the Home Networking Wizard performs the same 

tasks as ICS in the same sequence as discussed in the following 

list. 

Next, specify whether you are using a dial-up connection (modem 

or ISDN) or a high-speed connection (LAN, including cable modem 

or DSL). 

If you select dial-up, choose the dial-up connection (which must be 

set up already) you’ll be sharing, followed by the NIC (Network

186 


Interface Card) that connects you with the client PC’s that will 

share the connection. 

Windows will create a client configuration floppy and will prompt 

you to reboot the computer. 

When you view the Network Configuration in the Control Panel 

after rebooting, you should see the following: 

• Three “adapters” (your actual NIC, the Dial-Up adapter, and 

a new one called Internet Connection Sharing) 

• Three Internet Connection Sharing protocol entries, listing 

the previously mentioned adapters 

• Three TCP/IP protocol entries, listing the previously mentioned 

adapters 

The TCP/IP protocol entry for “Home” must point to the NIC that 

connects the clients to the host PC; the TCP/IP protocol entry 

called “Shared” must point to Dial-Up Networking; and the remaining 

TCP/IP protocol entry must point to Internet Connection 

Sharing. 

Also, check the TCP/IP configuration for “Home” (the NIC) and 

verify the IP address; it should be 192.168.0.1. This IP address must 

be provided to the computers that will share the Internet connection. 

If the settings aren’t correct, remove ICS and start over. 

Start an Internet connection on the gateway (host) computer 

before continuing. 

Configuring ICS on the Client Computers with a Windows 

9x/Me Host 

Although the ICS configuration process on the gateway (host) computer 

created a disk that can be used for setting up the ICS connection 

on client computers, most non-Microsoft sources advocate 

using manual configuration instead. The following steps are 

required: 

• Install the TCP/IP protocol on each client. 

• Set the Gateway option in the TCP/IP properties for each 

client’s NIC to the IP address of the gateway (ICS) computer: 

192.168.0.1 is the usual value (see above). Click Add to insert 

this value after you enter it.


• Use a Web browser on each guest to verify the connection is 

working; Internet Explorer should not have any dial-up settings 

configured for it, and should have no LAN settings 

enabled. The ICS client for Windows 98 disk selects Use a 

Proxy Server here, which is not correct. Netscape 

Navigator/Communicator should be set to Direct Connection 

to the Internet. 

• Some versions of Netscape Navigator might not work unless 

you create a Dial-Up Networking “adapter” on the guest and 

set its gateway as previously discussed. 

Reboot before you test the connection. 

Setting Up ICS with a Windows 2000 Host Computer 

Windows 2000 has built-in Internet connection sharing features. 

Log in as administrator before starting the following procedure. As 

with ICS for Windows 9x/Me, a LAN connection to the Internet 

must be shared by way of a second LAN card. 

To share a connection, follow these steps: 

1. Open the Network and Dial-Up Connections icon in the 

Control Panel. 

2. Right-click the connection you want to share and select 

Properties. 

3. Select the Internet Connection Sharing tab and enable sharing 

on your computer. 

4. If this is a modem connection, you can select the Enable On- 

Demand Dialing check box on the same tab as Internet 

Connection sharing. Enabling this feature launches the connection 

whenever other computers connected to this host 

computer need Internet access. 

To connect to a shared connection on a Windows 2000 host, follow 

these steps: 

1. Make sure you are running Windows 9x, Windows NT, or 

Windows 2000 Professional on your client. 

2. Verify that the NIC that connects your client to the host is 

set to the following: 

• Obtain an IP address automatically 

• Use DHCP for WINS resolution 

• Connect to a DNS server automatically

188 

(These settings require changes to the default settings for 

your NIC’s TCP/IP properties.) 

3. Adjust the Internet Explorer settings to the following: 

Note 


• Never Dial a connection 

• Use a LAN connection 

• Automatically detect settings 

• Don’t use automatic configuration script 

• Don’t use a proxy server 

Useful Web sites that cover this process in more detail include 

http://www.timhiggins.com/ppd/icsinstall.htm 

http://www.duxcw.com/digest/Howto/network/win98se/ 

The following Microsoft Web page answers common questions 

about Win98SE: 

http://support.microsoft.com/support/windows/faq/ 

win98se/w98seics.asp 

If you want the additional benefits of a proxy server, check out 

products such as WinProxy (www.winproxy.com), WinGate 

(www.wingate.deerfield.com), and Sybergen SyGate 

(www.sybergen.com). Many home-oriented networks and 

modems are bundled with these or similar products, so if you’re 

in the market for a new modem or are building a small network, 

ask whether a proxy server program for Internet sharing is 

included with your home or small-office networking kit.

7 

Parallel Ports, 

Printers, Scanners, 

and Drives 

Chapter 7 

Parallel Port Connectors 

Three different types of parallel port connectors are defined by the 

IEEE-1284 parallel port standard. In Figure 7.1, the DB-25 connector 

used on PCs for parallel cables (also called Type A) is on the left. 

The Centronics 36 connector (also called Type B) is in the middle. 

Virtually every parallel-interface printer, from the oldest dot-matrix 

to the newest laser printer, uses the Type B connector. Hewlett- 

Packard introduced the Type C connector and has added it to most 

of its recent laser printers, although it still uses the Type B connector 

as well. Type C is a high-density connector that uses a cable 

with an integral clip, as opposed to the clumsy, easy-to-lose wire 

clips used on the Type B port. 

2.089 

Type A 

2.716 

0.840 

1284 

Type B 

1.713 

370 

1284 

Type C 

Figure 7.1 The three types of IEEE-1284 parallel port connectors. 

You can see these connectors, along with all the others on the back 

of your system, in Chapter 14, “Connector Quick Reference.”

190 

Chapter 7—Parallel Ports, Printers, Scanners, and Drives 

Parallel Port Performance 

As printers have gotten faster and more devices are attached to parallel 

ports, the need for increasing parallel port speed has become 

more and more apparent. High-speed laser and inkjet printers, tape 

backup drives, CD-RW drives, and parallel port-to-SCSI converters 

can all benefit from using the fastest parallel port modes available 

on your system. 

Use the following tables to help determine whether your parallel 

ports are set to the fastest standard supported by your printers or 

other parallel port devices. On most computers, you adjust these 

parallel port settings through the CMOS/BIOS configuration 

screens. If the port is on an expansion card, you might use jumper 

blocks or a setup program to change the settings. 

Table 7.1 summarizes the various types of parallel ports, their input 

and output modes, speed, and hardware settings. 

Table 7.1 Parallel Port Types as Defined by IEEE-1284 

Parallel Port Input/ 

Type Input Mode Output Mode Output Speed Comments 

SPP Nibble Compatible Input: 50KB/ 4-bit input, 

(Standard (4 bits) second 8-bit output 

Parallel Output: 

Port) 150KB/second 

Compatible Input/Output Bidirectional Byte 

(8 bits) 8-bit I/O: 

150KB/second 

EPP EPP EPP Input/Output: 8-bit I/O, 

(Enhanced 500KB– uses IRQ 

Parallel Port) 2MB/sec 

ECP (Enhanced ECP ECP Input/Output: 8-bit I/O, 

Capabilities 500KB– uses IRQ 

Port) 2MB/sec and DMA 

EPP Versus ECP Modes 

Both EPP and ECP ports are part of the IEEE-1284 bidirectional parallel 

port standard, but they are not identical. Use the following 

table to understand how they differ, and consult your parallel port 

device manuals to see which mode is best for your system. 

Port Type IRQ Usage DMA Usage Designed For Notes 

EPP Yes No Tape drives, Version 1.7 predates 

(Table 7.2) CD-ROM, LAN IEEE-1284 standard; 

adapters IEEE-1284 version 

often called EPP 1.9

Port Type IRQ Usage DMA Usage Designed For Notes 

ECP Yes DMA 3 High-speed Many systems offer 

(Table 7.2) (Standard) printers, an EPP/ECP port 

DMA 1 scanners setting for best 

(Optional; results with all types 

default on of parallel port 

some Packard- 

Bell models) 

devices 

Some older parallel printers don’t recommend either mode and 

might print erratically if EPP or ECP modes are enabled. and ECP 

ports 

Prerequisites for EPP and ECP Modes 

To use these advanced modes, you must 

• Enable the appropriate mode on the parallel port (see previous 

section) 

• Use a parallel cable rated for IEEE-1284 uses 

Parallel Port Connectors 191 

The IEEE-1284–compatible printer cable transports all signal lines 

to the printer, is heavily shielded, and produces very reliable printing 

with old and new printers alike in any parallel port mode. IEEE- 

1284 cables can also be purchased in a straight-through version for 

use with printer-sharing devices. 

Parallel Port Configurations 

Table 7.2 lists the standard parallel port settings. While add-on 

multi-I/O or parallel port cards can offer additional settings, other 

settings will work only if software can be configured to use them. 

Table 7.2 Parallel Interface I/O Port Addresses and Interrupts 

Standard LPTx Alternate LPTx I/O Ports IRQ 

LPT1 — 3BC-3BFh IRQ 7 

LPT1 LPT2 378-37Ah IRQ 7 (LPT1) 

IRQ 5 (LPT2) 

LPT2 LPT3 278h-27Ah IRQ 5 

Testing Parallel Ports 

The most reliable way to test printer ports is to use a parallel port 

testing program along with the appropriate loopback plug. This 

method isolates the port and allows the system to capture output 

back as input. Parallel port testing programs are included in major 

diagnostic programs, such as Norton Utilities, CheckIt, AMIDiag, 

QA+ family, MicroScope 2000, and many others.

192 

Building a Parallel Loopback Plug 

Several loopback plugs are used for parallel ports because of the different 

testing procedures performed by the various diagnostic programs. 

If you have the correct pinouts, you can build your own, or 

you can purchase them directly from the diagnostic software company, 

either with the software or separately. 

Most use the IBM style loopback, but some use the style that originated 

in the Norton Utilities diagnostics. Check with your diagnostic 

software vendor to see which of these loopback designs is the correct one 

for your system, or if a different design is needed. 

The following wiring is necessary to construct your own loopback 

or wrap plugs to test a parallel port: 

• IBM 25-Pin Parallel (Male DB25P) Loopback Connector 

(Wrap Plug). Connect the following pins: 

1 to 13 

2 to 15 

10 to 16 

11 to 17 

• Norton Utilities 25-Pin Parallel (Male DB25P) Loopback 


2 to 15 

3 to 13 

4 to 12 

5 to 10 

6 to 11 


Troubleshooting Parallel Ports 

Table 7.3 Resolving Parallel Port Problems 

Symptoms Cause(s) Solution 

Device on port not Wrong parallel- Check device manual; probably 

recognized; can’t port setting need to change port to EPP, 

configure printer; 

printer won’t print 

ECP, or EPP/ECP mode. 

Wrong cable If you’re using EPP or ECP, you must use 

an IEEE-1284 cable.

Table 7.3 Resolving Parallel Port Problems Continued 

Printers 193 

Symptoms Cause(s) Solution 

Switchbox between All cables and switchbox must be 

device and IEEE-1284–compliant; remove 

computer switchbox and connect directly to 

device. If it works, replace noncompliant 

switchbox or cables. 

IRQ or I/O port EPP and ECP require a non-shared 

address conflict IRQ; use Windows 9x Device 

Manager to see whether IRQ for 

LPT (parallel) port is conflicting 

with another device; also check I/O 

port address and DMA. 

Device not Power on device before starting 

powered on computer. 

Port defective Use loopback and test software to verify 

data going out port is readable. 

Printers 

Printers can be attached to your computer in a variety of ways. 

Major interfaces used for printers include those listed in Table 7.4. 

Table 7.4 Printer Interface Standards and Recommended Uses 

Interface Type 

Required Benefits Drawbacks Operating System 

Parallel (LPT) Relatively fast, especially Regular printer Works with any 

if EPP or ECP modes are cable length operating system. 

used. Supported by restricted to 

virtually any application 10 feet due to 

that can print. No port signalloss. Daisyspeed 

or setup options chaining with 

required in most cases. other peripherals 

Standard cable works with doesn’t always 

virtually any PC and work. Printer must 

printer combination. be last device 

on daisy-chain. 

Serial Standard cable can reach Serial port speed, Works with any 

(RS-232/COM) up to 50 feet; use line word length, and operating system, 

drivers and phone cable stop bits must be but is obsolete for 

to reach hundreds of feet. set for both printer PC use. 

Printer can work with and application for 

terminals, PCs, or printing to work. 

Macintoshes with Very slow graphics 

appropriate cable. printing. Different 

printers require 

custom cabling.

194 


Table 7.4 Printer Interface Standards and Recommended Uses 

Continued 

Interface Type 

Required Benefits Drawbacks Operating System 

USB Faster than most parallel Driver problems Requires 

port modes. Devices can causing difficulty Windows 98, 

be daisy-chained through for many USB- Windows 2000, 

hubs in any order. Hot- based2 printers, or Windows Me1. swappable; printer can be especially certain 

moved to any USB-based 

system. Many devices are 

cross-platform–compatible 

with both PCs and Macs. 

HP inkjet models. 

PC Card Provides power to printer; Fragile PC Card Varies with printer. 

no electrical cord needed. can be broken or 

Allows design of very damaged. Printers 

compact printers for use with this interface 

with notebook computers. can’t work with 

desktop computers; 

might need to 

remove a PC Card 

from the notebook 

computer to enable 

printing. 

Network Enables sharing of a single, Requires network Works with any 

high-performance printer cards and config- network operating 

among many clients. Fast uration. Low-cost, system; check 

networks allow printing host-based printers printer for 

about as fast as local 

printing. Can “print” 

offline to queue and 

release when printer 

becomes available. 

can’t be networked. limitations. 

1. Windows 95 OSR2.1 also includes USB support, but many USB devices will not work with that 

version. Windows Me can use Windows 98 drivers, but a different driver is required for 

Windows 2000. More USB devices support Windows 98/Me than 2000. 

2. I recommend you purchase printers that can also be used with parallel ports in case of problems 

with USB sIupport. 

Printers also can be interfaced by IEEE-1394 and SCSI ports, but 

these implementations are used primarily by Macintosh systems 

with high-end inkjet or laser printers in graphic arts environments. 

Use Tables 7.5 and 7.6 to help you keep your printer running reliably. 

Hewlett-Packard PCL Versions 

Use Table 7.5 to determine which printer control language (PCL) 

features a printer offers, based on the version of HP-PCL it supports. 

You also can use this table to choose compatible printers in 

case you don’t have exactly the right driver for a given HP-PCL 

printer or compatible.

Printers 195 

Table 7.5 lists major printer models that support various versions of 

PCL. It is not exhaustive; check your printer’s manual for details 

about its PCL version and features. 

Table 7.5 

Versions 

Hewlett-Packard Printer Control Language (PCL) 

Version Date Models Benefits 

PCL 3 1984 LaserJet 

LaserJet Plus 

Full page formatting; vector graphics. 

PCL 4 1985 LaserJet Series II Added typefaces; downloadable macros; 

LaserJet IIP series support for larger bitmapped fonts and 

graphics. 

PCL 5 1990 LaserJet III, IIID, Scalable typefaces; outline fonts; 

IIIP, IIIsi HP-GL/2 (vector) graphics; font scaling. 

PCL 5e 1992 LaserJet 4, 4M, 4L, 600dpi support; bidirectional 

4ML, 4P, 4MP, communication between 

4 Plus, 4M Plus, printer and PC; additional 

5P, 5MP, 5L, 

5L-FS, 5Lxtra, 6L, 

6Lxi, 6Lse, 6P, 6MP, 

6Psi, 6Pse 

fonts for Microsoft Windows. 

PCL 5c 1994 Color LaserJet 

Color LaserJet 5, 5M 

Color extensions 

PCL 6 1996 LaserJet 4000 Faster graphics printing and return to 

LaserJet 2100 application; better WYSIWYG printing; 

faster graphics printing; less network traffic; 

better document fidelity and full backwardcompatibility 

with PCL 5 and earlier versions; 

uses object-oriented printer 

commands. 

PCL 6 requires a Windows 9x/NT/3.1 

printer driver; non-Windows operating systems 

can use a PCL 6 printer as a PCL 5e 

printer. 

Comparing Host-Based to PDL-Based Printers 

Most printers use a page description language (PDL). PDL-based 

printers receive commands from applications or the operating system 

that describe the page to the printer, which then renders it 

before printing. More and more low-cost printers are using a hostbased 

printing system in which the computer renders the page 

instead of the printer. 

Use Table 7.6 to determine which type of printer is suitable for 

your users.

196 


Table 7.6 PDL Versus Host-Based Printers 

Printer Type Feature Benefit Drawback 

PDL (includes Page rendered Printer can be used Higher cost because 

HP-PCL and in printer independently of a brains are inside the 

compatibles, PC or particular printer 

PostScript) operating system; 

MS-DOS support 

Host-based Page rendered Lower cost because Printer must be 

by computer brains are inside the married to a computer 

PC, not the printer with a compatible operating 

system and minimum 

performance 

requirements; non- 

Windows support is 

chancy; often can’t be 

networked 

Use Table 7.7 to determine the simplest way to test a printer. Note 

that host-based printers must have their drivers installed before 

they can print. 

Table 7.7 Testing Printers 

Printer Type Test Method 

Non-PostScript printer Enter DIR>LPTI from a command prompt (MS-DOS or 

using PDL or escape Windows 9x/Me); printer will print directory listing. 

sequences (HP-PCL, 

compatibles, dot-matrix, 

inkjet) 

PostScript printer You must send PostScript commands to the printer directly 

to test it without drivers. You can use PostScript printer test 

in Microsoft MSD or install correct drivers and use test print. 

(Windows 9x/NT/2000/ME offer a printer test at the end of 

the driver install process. This test can also be performed at 

any time through the printer’s icon in the Printer’s folder.) 

Host-based printer Install correct drivers and then use test print as earlier. 

Printer Hardware Problems 

Use Table 7.8 to track down problems and solutions with printers 

(any interface type). 

Table 7.8 Troubleshooting Printer Problems 

Printer 

Symptom Type Cause(s) Solutions 

Fuzzy printing Laser Damp paper Use paper stored at proper temperature 

and humidity.

Table 7.8 Troubleshooting Printer Problems Continued 

Printers 197 

Symptom 

Printer 

Type Cause(s) Solutions 

Inkjet Wrong paper Use inkjet-rated paper; check print 

type or setting and match settings and 

printer resolution to paper type; make 

settings sure you’re using correct side of 

paper (look for a “print this side 

first” marking on the package). 

Inkjet Cartridge Reseat cartridge; run cleaning 

clogged or utility; remove Canon cartridge 

not seated 

correctly 

from unit and clean printhead. 

White lines Inkjet Some nozzles Use nozzle-cleaning routine on 

through clogged printer or utility program in printer 

printed text 

or graphics 

driver to clean; retest afterwards. 

On Canon, HP, and other printers 

with removable printheads, clean 

printhead with alcohol and foam 

swab. 

On Epson and other models with 

fixed printhead, use cleaning sheet 

to clean printhead. 

On any model, replace printer cartridge 

if three cleaning cycles and 

tests don’t clear up clogging. 

Impact Pins in Remove printhead and clean with 

dot- printhead alcohol and foam swab; retest. 

matrix stuck or broken 

If pins are bent or broken, repair or 

replace printhead. 

Check head gap and adjust to 

avoid printhead damage; widen 

head gap for envelopes, labels, and 

multipart forms; adjust back to regular 

position for normal paper. 

Change ribbon; discard ribbons 

with snags or tears. 

Variable print Laser Toner unevenly Remove toner cartridge and shake 

density distributed in from side to side; check printer 

drum or toner position and ensure it’s level; check 

cartridge for light leaks; replace toner 

cartridge or refill toner. 

Fuzzy white Laser Dirty Clean corotrons per manufacturer 

lines on pages corotrons 

(corona wires) 

recommendation. 

Pages print Laser Broken charger Replace toner cartridge if it consolid 

black corotron tains corotron, or repair printer. 

Pages print Laser Broken Repair transfer corotron. 

solid white transfer 

corotron

198 



Symptom 

Printer 


Sharp, vertical Laser Dirty Clean developer if separate; rewhite 

lines developer unit place toner cartridge if it contains 

developer unit. 

Regularly Laser Spots less Clean fusing roller. 

spaced spots than 3 inches 

apart 

indicate 

dirty fusing 

roller 

Widely spaced Replace drum and fuser cleaning 

spots, or one 

per page, 

indicates 

scratched or 

flawed drum 

pad. 

Gray print Laser Worn-out drum Replace drum (most common with 

separate drum and toner supply) 

background. 

Loose toner Laser Fusing roller 

not hot enough 

Service fusing roller. 

Solid vertical Laser Toner cartridge Shake toner cartridge to 

black line nearly empty redistribute toner. 

Scratched drum Replace drum or toner cartridge. 

Paper jams Laser and Incorrect paper Use paper that is in proper 

and misfeeds inkjet loading; paper condition for printing; don’t 

too damp; overfill paper tray; don’t dog-ear 

paper wrinkled; 

paper too 

heavy/thick 

for printer 

paper when loading it. 

Envelope jams Laser and Incorrect Check correct envelope handling 

inkjet paper loading; procedures; consider using labels 

failure to set 

laser printer 

to use rear 

paper exit 

tray; printer 

can’t handle 

envelopes 

to avoid envelopes. 

Blank pages Laser and Paper stuck Riffle paper before loading paper 

between inkjet together; tray; make sure all paper 

printed pages paper is 

damp or 

wrinkled 

is the same size. 

Blank page Laser and Print spooler Change print spooler setting. 

between print inkjet set to produce 

jobs a blank divider 

page


Printers 199 

Symptom 

Printer 


Error light on Laser Memory or Reduce graphics resolution; simprinter 

flashes; overflow printer plify a PostScript page; reduce 

printer ejects overrun error number of fonts; check printer 

partial page memory size is accurately set; run 

(might require printer self-test to determine 

you to press amount of RAM onboard; add 

page-eject 

button) 

RAM to printer. 

Error light blinks; Laser Various causes Look up blink code in printer docno 

page ejected umentation and take appropriate 

or printed action. 

Error codes vary with printer 

model; check manufacturer’s Web 

site for a list of codes if the user 

manual is missing. 

LCD panel on Laser Various causes Look up error code or message in 

printer displays manual and take appropriate 

error code action. Error codes vary with printer 

or message model; check manufacturer’s Web 

site for a list of codes if the user 

manual is missing. 

Many less-expensive models use 

signal lights (see previous). 

Printer Connection Problems 

Use Table 7.9 to determine the cause and cure for problems with 

your printer connection. 

Table 7.9 Troubleshooting Printer Connections 

Printer Type 

Symptom Or Port Type Cause(s) Solutions 

Gibberish Any PDL used for Make sure print job is sent to 

printing print job correct printer; check default 

doesn’t match printer value; check port used 

printer for printer; check switchbox for 

proper printer selection; replace 

switchbox with LPT2 card or 

with USB-parallel cable. 

Damaged cable Look for damaged pins or insulation; 

use pinouts for each port 

type to test cable with a loop 

back plug or with a multimeter 

with CONT (continuity) function; 

retest with known-working cable. 

Serial port Incorrect speed, Both serial port on computer 

word length, and printer must be set to 

parity, and stop 

bits 

match.

200 


Table 7.9 Troubleshooting Printer Connections Continued 

Symptom 

Printer Type 

Or Port Type Cause(s) Solutions 

Use DOS MODE or Windows 

COM Port properties sheet to set 

serial port on computer. 

Printer configuration varies; might 

involve use of DIP switches, 

jumper blocks, printer setup 

panel, or software configuration 

program; see printer manual. 

Incorrect cable No such thing as a “universal” 

pinout RS-232 printer cable; check 

pinouts at both computer and 

printer end; rewire or reorder 

cable as needed. 

PostScript laser PostScript Check cable; check serial port 

preamble not 

properly 

received 

configuration; reload drivers. 

Printer Any Print job Check for paper out; reload 

not available has timed paper. Check printer cable or 

out; computer serial port settings; look for IRQ 

is using conflicts and correct them; set 

offline mode switchbox to automatic mode, 

to spool jobs or lock it to computer you want 

to print from. 

USB port Printer may not Check Device Manager; remove 

be detected by and reattach printer and 

Device Manager recheck. 

See Chapter 8 for other USB 

troubleshooting tips. 

Printer Laser and IEEE-1284 Ensure port and cable(s) and 

doesn’t notify inkjet connection switchbox are all IEEE-1284 (EPP 

Windows of not working or ECP or EPP/ECP); check cable 

paper out, connection; CMOS/BIOS configjams, 

out of uration. Install ECP LPT port 

toner or 

ink, etc. 

driver in Windows. 

Intermittent Any Bad switchbox Use direct connection to 

or failed or cables printer; check cables; replace 

communi- rotary-dial manual switchbox 

cations with 

printer 

with autosensing switchbox. 

Parallel port Device daisy- Use printer only; change 

chain with order of daisy-chain; avoid 

printer use of Zip, scanner, and 

printer on single LPT port.

Table 7.9 Troubleshooting Printer Connections Continued 

Printers 201 

Symptom 

Printer Type 

Or Port Type Cause(s) Solutions 

USB port Hub or driver See Chapter 8 for USB trouproblems 

bleshooting tips. 

Port busy; Laser and ECP port prints Use Windows 9x/Me Control 

printer inkjet too fast for Panel to load standard LPT driver 

goes offline printer in place of ECP driver; change 

setting in BIOS to EPP or 

bidirectional. 

If your USB printer can also be used as a parallel printer, use the 

parallel (LPT) port if you cannot solve print quality or reliability 

problems when you use it in USB mode. 

Printer Driver and Application Problems 

Printers use driver software to communicate with operating systems 

and applications. Use Table 7.10 to solve problems with drivers and 

applications. 

Table 7.10 Troubleshooting Printer Drivers and Applications 

Symptom Printer Type Cause(s) Solutions 

Prints okay Any Printer driver Reload printer driver and test; 

from command damaged or reinstall printer driver; switch 

prompt buggy to compatible new version that 

(DIR>LPT1), 

but not from 

applications 

can be downloaded. 

Form-feed Laser Incomplete Normal behavior for Printlight 

comes page sent Screen or envelope printing; 

on, but to printer eject paper manually; otherwise, 

nothing prints reinstall driver. 

Incorrect Laser or inkjet Printer using Check driver setting to 

fonts print internal determine which fonts will be 

fonts instead 

of TrueType 

used. 

Incorrect Any Printer If you change printers or plan 

page breaks changed to use a fax modem to print 

between your document, select the 

document printer and scroll through your 

composition document first to check page 

and printing breaks due to differences in font 

rendering and so on; correct as 

needed. 

Page cut off Laser or Margins set Reset document margins; use 

on left, inkjet beyond “print to fit” to scale page or 

right, top, printable area document to usable paper 

or bottom of printer size; check for proper paper 

edges size set in printer properties.

202 


Troubleshooting Parallel Port and 

Other Types of Scanners 

Scanners are among the most popular add-ons to computers, but 

they can cause plenty of problems for users. Use Table 7.11 to help 

make scanning trouble-free. 

Table 7.11 Scanner Troubleshooting 

Interface Type Problem Causes Solution 

Parallel Slow scanning Wrong port Use ECP or EPP 

speed setting mode per scanner. 

Scanner not Problems with Shuffle order of scanner and 

recognized daisy-chain non-printing device; check 

when scanner port settings; try scanner by 

used with itself; install second parallel 

non-printer port; make sure SCSI/ 

devices or Parallel scanner set for 

as third item parallel mode; check device 

(printer, driver setup during boot; 

scanner, and and set SCSI/Parallel 

anything else) scanner for SCSI mode; 

check cable. 

SCSI Scanner not Termination Terminate scanner only if 

recognized set wrong; last device in SCSI daisywrong 

SCSI chain; look for switch or 

ID; no terminating plug and check 

drivers operation; check SCSI IDs 

installed already in use and select an 

unused number; install 

TWAIN or ISIS drivers as 

well as SCSI drivers; check 

cable. 

USB Scanner not USB port not Enable USB port in BIOS or 

recognized working or install card; check port for 

not present IRQ conflict; use Windows 

98, ME, or 2000 to avoid 

support problems with 

Windows 95B; get updated 

drivers; check cable. 

All Scanner worked TWAIN.DLL Use Windows 98’s Version 

with Windows file was Conflict Manager to 

95, but not replaced by determine if TWAIN.DLL 

after Windows Windows 98 was replaced; use the 

98 upgrade original version (backed up 

by VCM). 

Scanner not Scanner turned Turn on scanner, open 

recognized off when system Windows 9x/Me/2000’s 

booted Device Manager and refresh 

devices; if this doesn’t work, 

leave the scanner on and 

reboot the system.

Table 7.11 Scanner Troubleshooting Continued 

Parallel Port Drives 203 

Interface Type Problem Causes Solution 

Acquire TWAIN or ISIS Verify scanner detected by 

command in drivers not system; if scanner works 

Photoshop or properly installed with its own software (not 

other or registered in launched from another 

programs system Registry; application), reinstall 

won’t launch scanner turned drivers and verify Acquire 

scanner off command works. 

Graphics look Wrong Use Table 7.12 

distorted scanning mode to determine best scanning 

during scan set for 

document 

mode by document type. 

Use Table 7.12 as a quick reference to help determine the best scanning 

mode for your documents. 

Table 7.12 Recommended Scanning Modes for Document Types 

Color B&W Photo 

Document Type Photo Drawing Text Scanning Mode 

Line Art No Yes Yes No 

OCR No No Yes No 

Grayscale No Yes 1 No Yes 

Color photo Yes No No Yes 2 

Color halftone Yes 3 No No No 

Color drawing No Yes No No 

256-color No Yes No No 

Copy/fax Yes 4 Yes 4 Yes 4 Yes 4 

1. Recommended only for drawings containing pencil shading and ink wash effects 

2. Use to convert color to black and white if photo-editing software conversion is unavailable or 

produces inferior results 

3. Adjust halftone options to match output device’s requirements 

4. Use to prepare scanned image for sending as fax or when image will be photocopied; converts 

all tones to digital halftones 

Parallel Port Drives 

Parallel ports were originally designed for printing, but have been 

pressed into service for many different tasks, including tape, optical, 

and removable-media drives. 

Use Table 7.13 to help you get the most from parallel port interface 

drives.

204 


Table 7.13 Troubleshooting Parallel Port Drives 

Drive Type Problem Solution 

Any drive type Drive not detected Check power and tighten cables; refresh 

in Device Manager 

or backup program 

Device Manager. 

Restart system if necessary; rerun drive 

installation software or tape backup 

installation software. 

Any drive type Slow operation Use fastest parallel port mode (EPP or 

ECP) available. 

Use drive or backup program setup utility 

to adjust speed of port. 

CD-R/CD-RW Buffer underruns; Use fastest parallel port mode (EPP or 

drive can’t make CD-Rs 

reliably 

ECP) available. 

Reduce write speed. 

Avoid using computer for other tasks 

while making CD-R. 

Use packet-writing with CD-Rs to reduce 

load on CPU if media will be used on 

computers that can accept multisession 

CD-Rs.

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