Building MIT PC/IP, or making apple pie

“If you want to make a pie from scratch, you must first create the universe”

–Carl Sagan

A little while ago I had touched briefly on the availability of of a PCC port to the 8086 done back in the early 1980’s that was hosted on VAX running 4.1BSD. I’d ruled it basically useless as you are restricted to 64kb .COM files, and I couldn’t get much of anything interesting running on it.

After all the fun of setting up NetManage Chameleon on Windows 3.0, over on IRC lys had mentioned I should try the MIT PC/IP stack. I never knew anything about it’s history but it became the first PC TCP/IP stack. You can read more about it from Internaut?

Dave Clark had gone to England for sabbatical and while he was there, had implemented TCP/IP in BCPL for the TRIPOS operating system, a predecessor of the Commodore AMIGA operating system. He brought the TCP/IP code back with him, and the Lab for Computer Science had a bunch of Xerox Alto workstations, and someone at LCS ported Dave’s TCP/IP to the Alto.

Then someone ported it to Version 6 UNIX and rewrote it in C. And that was what we took, and ported to PC DOS. At that point there were no C compilers that ran on the PC, and we were using a compiler that ran on a PDP 11/45 on Version 6 UNIX, and then on a VAX 750 running BSD v4.1. That was the AT&T; portable C compiler, and a group of people on the fourth floor of the LCS had written an 8088 code generator for it. This was before Microsoft C, and before 4.2 BSD.

Our first tasks were to bring up TFTP, TCP, and a telnet client under DOS. Several people were involved. Lou Konopelski did the initial TCP and telnet work, and Dave Brigham did similar work to what I did.

John Romkey – InternautHow PC-IP Came to Be

What is even more notable about PCIP is that it’s the reason the whole ‘MIT License’ even exists, as word seems to have spread quickly about a TCP/IP stack for the IBM PC compatible market. Jerome Saltzer has documented it all, if you want to read about it (WARNING PDF!)

Romkey would even then go on to found FTP software in that wonderful pre public internet era, before the eternal September.

Over on bitsavers there are 3 files:

[   ]8086_C_19850820.tar2019-03-12 14:36750K 
[   ]PC-IP_19850124.tar2019-03-12 11:534.6M 
[   ]PC-IP_19860403.tar2019-03-12 11:536.9M 
bitsavers.trailing-edge.com/bits/MIT/pc-ip/

Of course, the one thing that stands out is that these files look tiny. They aren’t even compressed! PCC, or the Portable C Compiler was released from AT&T, itself written in C, to make porting the C compiler easier to further allow Unix to be further easily ported. Now that I kind of had a mission, I decided to take the 8086 PCC leap, again.

Get the time machine ready!

A man, his best friend and a time machine! – Microsoft Sydney

Thankfully I had that 4.1c BSD image still up on sourceforge, aptly named: 4.1c BSD.7z, so I could follow my old instructions to create the tap file and start working with 8086 C, going back from 1985. And in no time, I had re-built the compiler, and assembler up and running. But I wanted more, as much fun as 4.1BSD is, I wanted to run everything natively on Windows.

At this point I’d remembered that this setup is a bit odd in that the object files that the assembler produces are OMAGIC (type 0407) a.out files. Thinking back to my old project of building Ancient Linux on Windows using vintage tools, it also uses OMAGIC a.out files! It’s not that unexpected as the original GNU ld linker from 1986 has hooks for both old magic & new magic (OMAGIC/NMAGIC) files, as this would be consistent from the era. Thinking this was my out, I might have a way of migrating the build process off of the VAX.

The first pass was to try to pull in all the VAX includes into my native Visual C++ 1.0, and get it to build with Microsoft C/C++ 8.0. The next thing to do of course, is look for where it’s doing anything with binary files and make sure it’s all set to O_BINARY/”rb”/”wb” where appropriate as MS-DOS/Win32/OS2 all handle text files differently from binary data. There is also fights with mktemp along with procedure name creep, like how ’round’ wasn’t a thing in 1980 but it sure is by 1993! Before the era of the 486DX/68040/Pentium not everyone had a math co-processor (FPU) so it’d make sense that a lot of things wouldn’t have this by default.

As a quick refresher the following diagram may be specific to the GNU GCC compiler, but the older PCC compiler uses the same methodology of first pre-processing files, then compiling them, assembling the resulting compiler output, then finally linking to an executable program. ( See – “So it turns out GCC could have been available on Windows NT the entire time“)

a rough explanation of how old C compilers work in stages

The steps for PCC 8086 are quite similar but to spell them out:

  • Pre-process with GNU cpp
  • Compile with PCC’s c86
  • Assemble with PCC’s a86
  • Link with GNU’s ld
  • Extract the MS-DOS .COM file with cvt86

There isn’t much to talk about the pre-processor, so I’ll skip it, suffice to say from my cl386 research, and porting GCC to OS2/NT, it just worked.

Compiling the compiler

Surprisingly getting the compiler running wasn’t too difficult. I do remember getting this running before, so seeing it run again wasn’t too much of a surprise. The simple C program:

main(){
printf("hi from 8086 pcc\n");
}

Gives us the following generated assembly:

        .data
        .text
        .globl  _main
_main:
        push    bp
        mov     bp,sp
        push    si
        push    di
        sub     sp,#LF1
        mov     ax,#L14
        push    ax
        call    _printf
        pop     cx
L12:
        lea     sp,*-4(bp)
        pop     di
        pop     si
        pop     bp
        ret
        LF1 = 0
        .data
L14:
        .byte   104,105,32,102,114,111,109,32
        .byte   56,48,56,54,32,112,99,99
        .byte   10,0

So far, so good, right! Even for fun, I was able to build it using Microsoft C 6.0! I figured I may as well try to get as much out of that purchase as possible.

Strage binary formats in a strange world

One thing that was a constant problem for me is that the assembler generated garbage, it never gave me the a.out OMAGIC file. Opening it up in a hex editor, Hex Editor Neo, and it showed problem, right away.

A simple do nothing program, assembled on the VAX

The OMAGIC sequence in hex should be written down as 07 01, but when I looked at the output from my PC port the file was not only too big but it didn’t have the headder:

The same program assembled on the PC

As you can see it’s just a bunch of zeros up front. Later on, I’d realize this was a ‘pad’ so it could be filled in later by the assembler when doing relocations. The file in question was rel.c which also should have been the hint. I don’t know if anyone saw it, but let me highlight it for you:

The OMAGIC header is being appended!

As you can see, where the file ends on the VAX, on the PC the OMAGIC header is being appended. I did a simple cut & paste in the editor, and the object file validated just fine. So why was this happening? In my rush to just add ‘binary’ flags to any file operations I had seen this in rel.c:

		(dout = fopen(Rel_name, "a")) == NULL)

I had taken this be an ‘append’ for whatever reason it would need to do that kind of thing. Well maybe that’s what it means in 1993, but in 1981 it doesn’t append, instead it just opens it normally. Is this a bug in the assembler, or a feature of 4.1BSD? Without debugging it, I just modified it to not append, as this was the only occurrence of an explicit append in the source code I could see.

		(dout = fopen(Rel_name, "wb")) == NULL)

And that did the trick, I now had a working assembler running on my PC!

But we are not out of the woods yet!

Naturally trying to build a much ‘larger’ Fibonacci program crashed the assembler. Luckily debugging it was a snap to find out that it was trying to free a static pointer. Or so I think. Today, in the future RAM is cheap, so I just commented out the offending free and now it was off to the linker.

When is advanced optimization a bad idea?

When the machine you wrote this for no longer exists. In the middle of the ld86 linker is this line:

		asm("movc3 r8,(r11),(r7)");

I have no idea why it’s there.

I don’t know what it should be doing.

This makes the linker un-portable.

However, as I’d mentioned before I did have the GNU linker that I’d successfully used to build Linux kernels, so there was hope!

C:\msvc32s\proj86pcc>\aoutgcc\bin\ld.exe -X -r -o hi.out crt0.b hi.b ./libc.a
C:\msvc32s\proj86pcc>cvt86 hi.out hi.com
C:\msvc32s\proj86pcc>msdos hi.com
hello from pcc for 8086!

I had now successfully run my first program without using the VAX. Although I had not mentioned a step yet, cvt86, this utility is described as creating a MS-DOS .COM file from an a.out file. I didn’t look into how it accomplishes this, but basically, it’s another linker. And this issue would come to complicate things as I had thought that everything was working.

libc & the heart of C

Libc, is simply put the central C library for getting everything done. While crt0 will setup the C environment everything else core from opening files, writing to the screen, and reading keyboard input is done through libc. So I thought re-building libc would be easy enough. To build the library you ‘archive’ them with the ‘ar’ archiver, then index them with ‘ranlib’. And again, from my a.out adventures building Linux I had both tools, however no matter what I was doing they did not work with cvt86. I wen’t back and rebuilt some kernels to verify, and yes it does generate archives but cvt86 was not happy.

I still had the SIMH VAX running in case I needed it, so I just broke down and figured I’d just port the VAX ar/ranlib to the PC. I don’t know off hand what the problem was, and I didn’t feel like spending an eternity to try to correct it, and both of the programs are somewhat portable. But of course it wasn’t that simple as ar opens files in strange ways that work on 4.1BSD but yeild chaos on the PC.

#define ARMAG   "!<arch>\n"

#define SARMAG  8

#define ARFMAG  "`\n"

‘ar’ has it’s own magic, a simple !<arch> and a ` followed by a new line. On any UNIX the \n is 10 in decimal 0xa in hex. But on the PC it’s carriage return and linefeed! And yes despite setting all the opens to binary, it was constantly injecting carriage returns & linefeeds all over the place! Some-how the file was being opened in text mode. Thankfully debugging even in old Visual C is great and inspecting the temporary files lead me to find this part:

			f = creat(file, larbuf.lar_mode & 0777);

In a few places it uses the creat (or create call. In an interview Dennis Ritchie had mentioned that this was one of his regrets in life, not naming creat create) call, which of course never has to set a mode, as everything is binary in Unix, unlike the PC. Great.

Luckily the fix was very simple after every creat, simply set the file mode to binary.

			setmode(f,O_BINARY);

Great!

Apple pie!

Fibonacci sequence

Now I could re-build libc from source and link it to the Fibonacci program!

Yes it’d take this long to get to the point where I can now easily edit file on a modern machine and have a Win32 native toolchain! VAX no longer required! We’ve successfully extracted everything we needed from the 1980’s!

First contact!

Now it’s time to look at what brought us on this adventure, MIT PC/IP.

The MIT PC/IP (PCIP) does require changes to the libc to work correctly. Unfortunately, they didn’t provide the full copy of the libc, but rather some ed scripts. So, the first question is do I even have the version these are based off of to start? I don’t know, so I had guessed, and I had guessed incorrectly.

3com 3c501

Configuring PCIP is somewhat involved, first you need MS-DOS 2.00 or greater which thankfully in the future is FREE! The next thing you need is a 3com 3c501 card. This is going to be a challenge but it’s just as any good time to mention 86box, and the latest version that I’ve been using that of course supports this kind of setup!

New version 4.1.1

I can’t recommend it enough, 86box is like all the inconveniences of old software & hardware without having to spend a fortune for weird combinations, fighting to have space for it. I naturally setup a 386sx with CGA, 20Mb hard disk and a 3c501 card. It’s nice being able to also be very task specific, this doesn’t have to be a DooM/Quake machine!

the first thing you need to do is add the netdev.sys device driver that is created as part of building PCIP from source. a simple:

DEVICE=\NETDEV.SYS

in your config.sys is more than enough. However, how do you configure it? Well it’s the ‘custom’ program that binary edit’s the device driver.

YES, IT EDITS THE DEVICE DRIVER.

Setting stuff up is somewhat straight forward, however it displays TCP/IP information in decimal not in hex. I haven’t even looked into the how or why.

The first page

The first page options are kind of banal, it’s back in the day when people would use finger to find people on the internet and call them up or send emails. How cute. 1985 was a different world!

hardware options

In the hardware options the only thing to check is the I/O base, IRQ & DMA for the Ethernet card. I just configured the card around 0x300/5/1 as it’s great being purpose built!

telnet options

There is a separate window for telnet options. Naturally high speed connections frame far too fast for something built from 1985. I found lowering the TCP windows really helped with pacing.

Site config

As I had mentioned the site configuration displays all the information in decimal. Also, I’m wasn’t sure what is going on with the netmask, but looking at the old Windows calculator revealed it was being stored in OCTAL. It’s probably why the addresses have commas instead of periods. Although I had configured DNS it didn’t work, as it uses UDP port 42. It’s clearly doing something very early 1980’s.

The status CR/LF is broken!

So close and yet so far away. The only thing to do was try to figure out which of the libc stuff was ‘newest’ in the pure state and try to figure out where to go from there.

Redo!

While I had not configured the libc correctly, I had partial success! I could actually establish a telnet session! Libc wasn’t working correctly as every line feed didn’t generate a carriage return, as you’d need for MS-DOS leaving it with broken status.

But at the same time, despite all the weird ‘challenges’ for the most part ‘it just worked’. Which is pretty cool!

It turns out the answer was the 8086_C_19850820 file. As far as I can tell there was only one thing that didn’t patch correctly but I was able to build a libc in no time.. that didn’t work. In the patch it removes ulrem/auldiv from arith.a86 Not sure why, I haven’t messed with it. But that means I had to restructure to build with the non floating point n86c compiler as that’s the way PCIP is expected to be built. After rebuilding with this compiler and this seemingly properly patched library I finally had it working!

Ping my local gateway!

Instead of a garbled mess, I had something I could read!

telnetting to my test BBS

Now instead of a garbled mess, I can see it was trying to display the connected IP, and a clock.

Sadly it doesn’t work with SLiRP. I’m sure it’s either classful routing or it really doesn’t like how SLiRP handles ARP. I suspect it’s also trying to do old style classful routing as well, which means you can’t just load arbitrary subnet masks wherever you want, to try to squeeze the 4 billion IP’s out of the internet.

The updated telnet client connecting to a test BBS

Final thoughts

I suspect that although there were binaries in the above tar files, going through the effort to rebuild PCIP really wasn’t all that expected for most people to carry out. Sadly, there was no shared source ‘sites’ online, and we’re lucky enough someone kept a few tarballs lying around. I really can’t blame them for sticking with then current development tools, especially for what you’d need to build a C compiler back in the early 80’s. It’s a shame the QL or the Macintosh didn’t have the RAM or the DASD capacity to become that home cross compiler of the 80’s.

Most project just require you to work on that actual project, while this has been a substantially larger undertaking from anything normal, but I guess I’ve learned a bit along the way with all those “pointless” GCC port things I’d done, well it turns out they are incredibly useful! It’s been a fun archeological expedition for me, thankfully C is still a thing, I wonder what happened to all the ADA/Perl/Pascal/”Wave of the future” stuff that is always disappearing. At least more and more people work on full system emulation so there is always that!

For anyone that curious you can find all the code over on github:

https://github.com/neozeed/8086pcc

Against my better judgement, I’ve added a binary package on github.

The Rise of Unix. The Seeds of its Fall. / A Chronicle of the Unix Wars

It’s not mine, rather it’s Asianometry‘s. It’s a nice overview of the rise of Unix. I’d recommend checking it out, it’s pretty good. And of course, as I’m referenced!

The Rise of Unix. The Seeds of its Fall.

And part 2: A Chronicle of the Unix Wars

A Chronicle of the Unix Wars (youtube.com)

Years ago I had tried to make these old OS’s accessible to the masses with a simple windows installer where you could click & run these ancient artifacts. Say 4.2BSD.

Download BSD4.2-install-0.3.exe (Ancient UNIX/BSD emulation on Windows) (sourceforge.net)

Installing should be pretty straight forward, I just put the license as a click through and accept defaults.

Starting BSD via ‘RUN BSD42’ and the emulator will fire up, and being up a console program (Tera Term) giving you the console access. Windows will probably warn you that it requested network access. This will allow you to access the VAX over the network, including being able to telnet into the VAX via ‘Attach a PTY’ which will spawn another Tera Term, prompting you to login.

telnettting into the VAX

You can login as root, there is no password, and now you are up and running your virtual VAX with 4.2BSD!

All the items

I converted many of the old documents into PDF’s so you may want to start with the Beginners guide to Unix. I thought this was a great way to bring a complex system to the masses, but I’m not sure if I succeded.

776 downloads

As it sits now, since 2007 it’s had 776 downloads. I’d never really gotten any feedback so I’d hoped it got at least a few people launched into the bewildering world of ancient Unix. Of course I tried to make many more packages but I’d been unsure if any of them went anywhere. It’s why I found these videos so interesting as at least the image artifacts got used for something!

But in the off hand, maybe this can encourage some Unix curious into a larger world.

Other downloads in the same scope are:

Enjoy!

86 DOS Version 0.11 found!

86-DOS on archive.org

As of this moment, this is the oldest version of 86-DOS surviving in the wild. The prior version was 0.34. You can download a disk image over on archive.org. Thanks to F15sim for providing the uploads!

Getting this running was a little involved as I first had to build open-simh, I just used the Windows Subsystem for Linux (WSL) to build the altairz80 emulator. With the emulator built, you’ll need the BIOS 86mon.bin from schorn.ch as 86dos.zip. In the archive you’ll find 86-DOS 1.0 in the zip file. Simply editing the file 86dos and specifying the 0.11 download (I renamed it as it’s too long and too many spaces!) and you’ll be able to run 86-DOS.

86-DOS booting up on open-simh

There isn’t much on the diskette:

  • COMMAND COM
  • RDCPM COM
  • HEX2BIN COM
  • ASM COM
  • TRANS COM
  • SYS COM
  • EDLIN COM
  • CHESS COM
  • CHESS DOC

There is a simple chess game, although I’m not much of a player..

A:chess

Choose your color (W/B): W
Ply depth (1-6): 1
E2-E4
e7 e5

There is no source code in this disk image, but there is some stuff on the 0.34 image.

Just a quick post in that middle of the night.

2,000 monthly downloads!

Well this is a bit ambiguous. As Im waking up to check emails I get this notice:

Congratulations! Ancient UNIX/BSD emulation on Windows has just been recognized with the following awards by SourceForge:

Community Choice
SourceForge Favorite

These honors are awarded only to select projects that have reached significant milestones in terms of downloads and user engagement from the SourceForge community.

This is a big achievement, as your project has qualified for these awards out of over 500,000 open source projects on SourceForge. SourceForge sees nearly 30 million users per month looking for, and developing, open source software. These award badges will now appear on your project page, and the award assets can be found in your project admin section.

-sourceforge email

So yeah, and here we are:

Nothing like standing on the backs of giants!

Naturally ready to run favorites include:

And of course for the DIY enthusiasts:

Honorable mention goes to the 4.3BSD UWISC enthusiast that downloaded Apache, AberMUD, and lynx!.

Playing Mel Kaye’s LPG-30 Black Jack

Oh sure, the tale is as old as time itself, but how does one play the original Royal McBee LPG-30 game?

Something very Fallout’esque about this modern miracle of miniaturization!

Thankfully it’s all covered here: Using the SIMH LGP-30 emulator | Obsolescence Guaranteed

For the impatient the short story is this on a SIMH LGP prompt:

SET CPU LGP30
SET CPU TAPE
LOAD BKJCK.TX
SET CPU MANUAL
G -T 4500
g

Naturally you’ll need the game as well which is currently on FTP at ftp.informatik.uni-stuttgart.de . Obviously thanks to our google overlords FTP is no longer integrated in the browser because the browser is only http, not gopher, telnet, ftp .. who needs to be universal?

You’ll find it in the /pub/cm/lgp30/papertapes/Games directory.

Important things is that your yes/no should be inputted as y’ or n’ The game will stop SIMH so you need to ‘g’ to start again.

FUN!

Although this comes up time and time again, I found this hacker news post, that actually has a picture of Mel, showing that he was in fact a real person.

The Gould SEL Concept 32/87

Despite Gould’s location being a few minutes drive from where I first arrived in America, I never had any idea they existed, were making their own exciting machines, or were even a Unix VAR. At a time during the Unix wars one was left to choose SYSV or BSD, but Gould had gone another direction with UTX with a ‘why not both’ approach. Truly an 80’s miracle of Unix.

Well as luck has it there is a SIMH emulator! James C. Bevier has a project on github where he’s building his SEL32 emulation on SIMH!

Even better he’s included tape images, and working INI files which I was able to make into a working system! (after some help with a tape bug)

Boot
File is COFF format
-> section (.bss) size (177960) clearing at (0xcbc18)
-> section (.text) size (724800) loading at (0x1200)
-> section (.data) size (105176) loading at (0xb2140)

Start 0x1200

UTX/32 2.1B (exp) #0: Mon Apr 10 19:46:05 GMT 1989
    bsln@fenix:/usr.POWERNODE/src/src/sys/obj

V6 CPUIPU(P) configuration (IPU not present)
top of system = 0x400000
real mem = 8388608
End of kernel map 0x218464
avail memory = 7356416
using 256 buffers containing 262144 bytes of memory
using 256 mirror buffer headers
ioi: channel iop0 at 7e00 online
ioi: channel dc0 at 800 online
ioi: channel dc1 at c00 not present, dci cc=2
ioi: channel dc2 at 400 not present, dci cc=2
ioi: channel tc0 at 1000 online
ioi: channel en0 at e00 online
 -- CHECK AND RESET THE DATE!
swapping on the b partition
dmmax 512 mbswap 3576
dumplo 11776
Checking root filesystem
Check commented out, uncomment once you have edited /etc/fstab!
Automatic reboot in progress...
Mon Aug 30 05:35:46 CDT 2021
/etc/fsck -p /dev/rdk0d
/etc/fsck -p /dev/rdk0e
/etc/fsck -p /dev/rdk0f
File systems OK

Mon Aug 30 05:36:06 CDT 2021
Mounting file systems
/dev/dk0d mounted on /usr.POWERNODE
/dev/dk0e mounted on /home
/dev/dk0f mounted on /usr/local
Initializing loopback
Starting line printer daemon
Starting standard daemons: update cron.
Adding swap partitions
Standard setup functions
Invoke local rc file
Entering /etc/rc.local
dumpdirectory: No such file or directory
Starting Syslog Daemon
Starting local daemons: inetd.
Starting NFS/RPC daemons: portmap sund.
Mounting NFS filesystems
Leaving /etc/rc.local
Starting mail
Checking aliases file
Preserving editor files
Clearing /tmp - does not remove directories
Clearing pseudo terminals
Leaving rc
Mon Aug 30 05:36:07 CDT 2021


GOULD UTX/32 2.1B (noname) (console)

login:

It’s very BSD feeling on the boot and in the /usr directory there is 5bin 5lib

Sadly transferring stuff by just pasting on the console reveals that there is some IO issues in the simulator:

syncing disks... done

dumping to dev 101, offset 11776
ioi: channel dc0 at 800 online
dump succeeded

As a matter of fact doing anything too fast can/will panic the simulator. That goes for Ethernet and additional serial ports.

Interesting highlights of the platform:

Produced by hard-params version 4.1, CWI, Amsterdam
Compiler does not claim to be ANSI C

Char = 8 bits, signed
Short=16 int=32 long=32 float=32 double=64 bits
Char pointers = 32 bits
Int pointers = 32 bits

Alignments used for char=1 short=2 int=4 long=4
Character order:
    short: AB
    int:   ABCD
    long:  ABCD

Obvious issues with the platform is a lack of GCC. The PCC compiler while standard for early 80’s non PDP-11/VAX machines is a bit lacking as the years went on. I was unable to build gzip due to the following error:

# gmake
cc  -o gzip gzip.o zip.o deflate.o trees.o bits.o unzip.o inflate.o util.o crypt.o lzw.o unlzw.o unpack.o unlzh.o getopt.o
ld: warning: near subsegments too big for static base spanning
ld: gzip.o:
        no base for reloc of memref instruction at .nbtext+0x18 relative to symbol _progname
ld:
        1221 more 'no base ' errors
gmake: *** [gzip] Error 4

Sadly I don’t find much on Altavista other than this & this. It only offers this terse comment:

The constraints on address space on a Gould are quite severe.

Bummer. Additionally neither Hack 1.0/1.03 or PDP-11 Hack will build either. Surprisingly bash-1.14.7, make-3.75 and ircii-2.5 compiled. Obviously with no networking IRC is kind of pointless.

It’s an interesting time capsule of life outside of AT&T/CSRG or SUN, going in a different direction. It seems like a larger lost opportunity to take their ‘it runs both’ approach software and not have it available on different platforms. Granted for a hardware company once the software leaves the compelling reason to buy the hardware evaporates. Hello NeXT.

If anyone wants to try to re-create it, download and build the SEL32 emulator from github, and I put my vague instructions here.

Or for like minded OS tourists, you can give it a spin here: UTX32_2.1B.7z. I included a ‘9346-UTX-blank.disk’ file which is already prepared if you don’t want to go through the 15 questions to prep a disk. Likewise I made a ‘9346-UTX-biga-blank.disk’ image which is just a single large ‘a’ partition as it’s trivial to just add a bunch of big disks these days.

Full 32bit Unix machines from Ft Lauderdale! Who knew?

Confessions of a paranoid DEC Engineer: Robert Supnik talks about the great Dungeon heist!

What an incredible adventure!

Apparently this was all recorded in 2017, and just now released.

It’s very long, but I would still highly recommend watching the full thing.

Bob goes into detail about the rise of the integrated circuit versions of the PDP-11 & VAX processors, the challenges of how Digital was spiraling out of control, and how he was the one that not only championed the Alpha, but had to make the difficult decisions that if the Alpha succeeded that many people were now out of a job, and many directions had to be closed off.

He goes into great detail how the Alpha was basically out maneuvered politically and how the PC business had not only dragged them down by management not embracing the Alpha but how trying to pull a quick one on Intel led to their demise.

Also of interest was his time in research witnessing the untapped possibilities of AltaVista, and how Compaq had bogged it down, and ceded the market to the upstart Google, the inability to launch a portable MP3 player (Although to be fair the iPod wasn’t first to market by a long shot, it was the best user experience by far).

What was also interesting was his last job, working at Unisys and getting them out of the legacy mainframe hardware business and into emulation on x86, along with the lesson that if you can run your engine in primary CPU cache it’s insanely fast (in GCC land -Os is better than -O9).

The most significant part towards the end of course is where he ‘rewinds’ his story to go into his interest in simulations, and of course how he started SIMH when he had some idle time in the early 90’s. SIMH of course has done an incredible amount of work to preserve computing history of many early computers. He also touches on working with the Warren’s TUHS to get Unix v0 up and running on a simulated PDP-7 and what would have been a challenge in the day using an obscure Burroughs disk & controller modified from the PDP-9.

Yes it’s 6 hours long! But really it’s great!

Mach ’86 on the SIMH VAX

Kernel booting from 1986

While the kernel may boot on SIMH there is certainly something going on with the SIMH emulation of the hardware that threw me for a few loops. I had a pre-installed version of 4.3BSD which was on a RA81 disk but shortly after loading the kernel various binaries wouldn’t load, filesystems wouldn’t mount and of course the inevitable file corruption.

This led me to the fun of loading up 4.3 onto RP06 disks as they are smaller and I was hoping less prone to errors. During this fun, I found this page on plover.net, which as a fun filled tangent shows how to use the Quasijarus console floppy image to run the standalone programs. With the latest version of SIMH, I can run format and it initializes the disks, so I almost think it may be possible to do some kind of ‘native install’ on the VAX-11/780 SIMH, although It’s not what I was in the mood for.

So finally with an install over several RP06 disks, I was lucky enough to figure out how to build the Mach’86 kernel, and get it to boot, and then the corruption happened again. Luckily for me I had snapshotted the disks before experimenting and noticed how even those had issues booting up. It’s after a bit of searching I found that other people may have issues with SIMH’s Async I/O code, and the best thing to do, is just to disable it with a “set noasync”.

Now my disks could boot under the Mach kernel, and I could self host!

self hosted!

Setting up the build involved copying files from the ‘cs’ directory to their respective homes, along with the ‘mach/bin/m*’ commands to the /bin directory. Configuring the kernel is very much like a standard BSD kernel config, however the directory needs to exist beforehand, and instead of the in path config command run the config command in the local directory.

While maybe not perfect, keep in mind I haven’t found any real instructions as of yet, so this is more of a ‘wow it booted’ kind of thing at the moment.

While this kernel does have mentions of multi processor support I haven’t quite figured out what models (if any) are supported On the VAX, and if SIMH emulates them. While oboguev.net has a very interesting looking multiprocessor VAX emulation, VAX_MP it’s a fictional model based on the microvax, which I’m pretty sure 4.3BSD/Mach’86 is far too old for.

And for those who want to play along, here is a zip file of the disk images, emulator and config file I’m using, Mach86.zip

AT&T 3B2 400 emulated

This is super awesome!

AT&T 3B2 SYSTEM CONFIGURATION:

Memory size: 4 Megabytes
System Peripherals:

        Device Name        Subdevices           Extended Subdevices

        SBD
                        Floppy Disk
                        72 Megabyte Disk

        Welcome!
This machine has to be set up by you.  When you see the "login" message type
                                setup
followed by the RETURN key.  This will start a procedure that leads you through
those things that should be done the "first time" the machine is used.

The system is ready.

Console Login:

Back in the 1980’s AT&T shifted UNIX from being an internal research project that got somewhat popular in college spaces (and larger companies, General Motors was an early UNIX adapter, along with companies like Industrial Light and Magic).  Quickly after the divestiture of 1984, AT&T entered the commercial space with it’s own custom machines & their home made UNIX operating system.  Below is one of the ads they ran in 1984, touting their so called ‘super microcomputers’, featuring the 3B2, the 3B5, and the AT&T Personal Computer.

Thew new computers from AT&T

And indeed for many a government institute bewildered by the dozens of UNIX vendors, standards, and chaos of different platforms and processors many were all to happy to buy AT&T UNIX on AT&T machines.

And indeed this was my first experience with genuine SYSV Unix.

And I hated it.

Initially I had been thrown at an English computer lab because I knew how logon and do my work in style & diction, they decided I could help.  The system was aging and had major problems, as some prior students had figured out enough of the link kit that they would put their own attempts at re-writing portions of the kernel into the system, and it’d break.  Naturally the original installation diskettes were lost, and the best that could be done was basically shut it down throughout the day and run the disk repair utilities.  It was not a fun job.

Later on the 3B2’s were thrown into the ‘common garbage’ aka free kit for other departments, and the 3B2’s re-appeared at the next place I was volunteering at on campus.  However in addition to the two machines, there was a few other boxes of manuals, and oddly enough the installation diskettes.  And also about a dozen of these AT&T ISA Starlan adapters.  These weren’t the ones that were basically Ethernet (Starlan10) but rather the original ones.

Through some incredible luck we did find an NDIS 3 MS-DOS driver for the Starlan car, and we were able to cobble together a Starlan1 LAN consisting of a 3B2 that we cannibalized the RAM and disks from one of them to make a ‘super’ 3B2, with added TCP/IP software and a massively cut down port I did of samba to turn it into a tiny file & print server (72MB MFM disks were it’s biggest if I recall), along with Windows 95 clients.  And of course with a TCP/IP lan we could easily load a proxy server (WinGate?) on one machine with the 56kb modem, and now we all had internet access.  I know it’s sad today, but trust me back then it was “a big deal” that we had a fully functional LAN.

Over on loomcom.com there is an incredible amount of information about the reverse engineered WE32100, along with the 3B2 hardware, and of course information about the newest SIMH simulator the 3B2/400!

Instructions and disk images on the site made it incredibly easy to grab the latest SIMH Windows Development binaries, and get my own virtual 3B2 up and running in minutes! So naturally I pasted in dhrystone.c to see if it’d work.  And that was the first weird issue is that the backspace is the pound # key.  So all the C macro definitions lost their # sign.  I added them in vi without full terminal support because I’m crazy and:

# uname -a
unix unix 3.2 2 3B2
# ./dhrystone
Dhrystone(1.0) time for 500000 passes = 40
This machine benchmarks at 12500 dhrystones/second

Obviously this is 100% bogus, as the real machine should get around 735, and I didn’t even bother with the -O flag.

The current emulator doesn’t do any additional serial ports, nor any Ethernet adapters.  So you only get a console.  But with the pre-installed C compiler image, I was able to build a trivial file just fine.  Although pasting on the console really leaves a lot to be desired.

SDF AT&T 3B2/500 UNIX System

I know for some of us old people the 3B2 hid in the corners of our call centres, running our AT&T Definity switches, our voicemail, and even some of our early ISPs.  After funneling money into SUN to get them to work on SYSVr4 which was the grand unification of BSD + SYSV AT&T’s interest if UNIX quickly waned, and they divested themselves of UNIX, and eventually all PC hardware, although they did re-enter the PC space a few times before exiting yet again.

As time would tell, proprietary hardware + a previously ‘open’ operating system were not the winning combination.  And so far the only UNIX vendor to weather the Linux storm so far is IBM with it’s A/IX.

4.2BSD TCP/IP networking

I got this note from  Allen Garvin, that details his adventure in taking a stock 4.2BSD VAX image, getting it running on SIMH, and turning on the network stack.

Although 4.2 may have had security issues, (R Morris), and had some clear issues with scaling. Along with a whole host of other issues.  Naturally if you want something more ‘robust’ on modern networks, you’ll want 4.3BSD which corrected quite a number of issues.

You can read about it over on his blog.  It’s very good with step by step instructions, goes over retrieving the NIC driver, re-building the kernel, and getting it operational on our LAN.