SIMH v3.8-1 released!

A new bugfix version of SIMH has been released!

I’ll be adding more binaries onto the sourceforge page, but in the meantime, the sourcecode is up, win32 binaries & i386 linux binaries are also uploaded.

From the notes:
SCP and libraries: Fixed bug in DETACH ALL if called at simulator exit (from Dave Bryan) Fixed bug in DO command handling of null arguments (from Dave Bryan) Fixed bug in DO handling of \\ (literal backslash) (from Dave Bryan) Fixed warnings in help printouts HP2100 (all changes from Dave Bryan)
Corrected DMS violation register set conditions JSB to 0/1 with W5 out and fence = 0 erroneously causes MP abort Fixed DJP, SJP, and UJP jump target validation BACI: Fixed STC,C losing interrupt request on BREAK MPX: Implemented 12792C eight-channel terminal multiplexer MT: Fixed missing flag after CLR command PIF: Implemented 12620A/12936A Privileged Interrupt Fences IBM 1401:
Fixed bug in ZA and ZS (from Bob Abeles) Fixed tape indicator implementation (from Bob Abeles) Added missing magtape modifier A (from Van Snyder) Added -n (no rewind) option to BOOT (from Van Snyder) Fixed bug to mask input to 6b on read (from Bob Abeles) PDP11:
Moved all Unibus/Qbus support routines to common I/O library Fxed bug in ASHP left overflow calc Fixed bug in DIVx VAX:
Fxed bug in ASHP left overflow calc Fixed bug in DIVx Resync time of day clock on any clock reset

HECnet client for SIMH

Ok the good news is that my PS3 running SIMH/VAX/Quasijarus is pinging away on my OpenBSD machine running the HECnet bridge program…

The ‘bad’ news for now is that it’s all *nix based… so no joy for the windows crowd. I’ll fix this soon enough, and release some binaries…

For now you can read about it here:

Colossal Cave on the PDP-8 & OS/8 redux

Just an FYI I got a quick message from Rick Murphy regarding the OS/8 image for Adventure. The new image is now located here:

Naturally, check out his page with all the information regarding Adventure on OS/8 right here:

Once more again, special thanks to Rick for making this whole “adventure adventure” possible!!


While adding pages & stuff to I came across this thing called xv6 at MIT.

What it is, is a port of Unix v6 to the x86 cpu. Before this, apparently they were using actual v6 on a PDP-11 emulator, however for their uses it would be easier to use something more i386 like. Now the cool part is that it’s SMALL. It harkens back to the day when people could actually read the code to their OS..

# cat *.c wc -l
cat *.h wc -l
cat *.S wc -l

Yes, that all there is to it! It litteraly takes 4.5 seconds to compile the whole thing, and setup a boot/root disk image on a 1.5 Ghz P4. The only ‘catch’ is that you need elf tools to build the thing.. Most Linux/NetBSD/OpenBSD folk ought to be in luck as they have been elf for quite some time now.. For windows people it’s just easier to install an OS into a VM that contains an ELF toolchain.. Don’t feel bad about compiling it in a VM as it will not be that big of an ordeal.

Download the inital source from here:

If you feel brave go thru the labs.. They have stuff to add like virtual memory and whatnot, but they do walk you thru it, with guides and stuff… Remember this is out of a class, they don’t throw the kids to the wolves as it were.

Naturally since it’s v6, there is no TCP/IP, heck it doesn’t even have native tools… But it *can* run exe’s so it’s got enough to get your feet wet.. It’s dammed near tempting to complete the course work to flesh it out, grab 32v and start building a userland then bring it to 3BSD levels… But then I guess that is missing the point of a small readable Unix.

Anyways I found it interesting, no pictures on this one but either way its… different. Oh and the disk images run great under Qemu for what it’s worth.

Colossal Cave on the PDP-8 & OS/8

While I was tracking down some FORTRAN versions of Zork/Adventure I came across the original ‘advent’ for OS/8. Not realizing it at the time, but this ‘advent’ I had come across was not the ‘adventure’ of zork fame, but adventure of Colossal Cave fame. Colossal Cave was written by Willie Crowther and quickly became one of the most popular games for it’s time. Because it was written in FORTRAN it was portable to various machines, not limited to the original version for the PDP-10, to even the IBM-PC (Microsoft released it the same time as MS-DOS 1.0). The version in question has been expanded by Don Woods to include the fantasy aspect of it. And with SIMH it’s very easy to get running.

First you will need a PDP-8 emulator. Natrually I’d recommend SIMH. You can download source and binaries from the sourceforge page here:

With the emulator in hand, next I’d just recommend you use the disk image graciously provided by Rick Murphy with both OS/8 and the adventure program already compiled and indexed here:

Now all you need to do is setup an .ini file for the PDP8 emulator. It’s very easy just save this in a .ini file with the emulator in the disk image in the same directory. If you call it pdp8.ini it will auto execute when you run the pdp8 emulator.

set cpu 32K
set cpu idle
att rk0 advent.rk05
boot rk0

Now go ahead and run the emulator.

You will be greeted with a . prompt. Now type in:


This will run the FORTRAN runtime system… It’s funny to note that in this day and age we take things like runtime systems for granted as this kind of thing is bound to the exe, and we just run things never thinking of where they came from. There is no doubt the DLL has been an improvment over stuff like this from the 1970’s… Anyways with the FORTRAN runtime loaded we are now at a * prompt. We just have to tell it the FORTRAN program to run, in this case it’s ADVENT. So type in the following:


You will still be at the * prompt, to execute it, hit the escape key. Then you will get the following output:


Ok, now you are ready to enter the FORTRAN version of Colossal Cave under OS/8. And it shouldn’t have been *that* hard… 🙂

Now for anyone wondering about the original version of Colossal Cave, The original FORTRAN source to adventure has been located here:

And if anyone is brave enough, OpenWATCOM includes it’s FORTRAN compiler.. not to mention G77, and of course the original FORTRAN stuff that can be run in SIMH. I’d leave this up to the reader as my FORTRAN skills are… lacking. I don’t know if it’s me, but I started out with the IBM FORTRAN on the RS/6000 back in the AIX 3.2.1 days, and then went to Microsoft FORTRAN 5.. Now it seems I’ve forgotten just about everything, and what I do recall works on few and far of the things out there…. But that’s another story for another day. Oh and if you search around there is a C version of this….

Apple Lisa Xenix

Wow I’m surprised a few hours googleing about and I got it running….
I found this ‘idle’ emulator (“Incomplete Draft of a Lisa Emulator” ), which can infact run Xenix! It also says it can run the uniplus SYSV (so says the readme)..

Searching around I found the following site:

Whas Xenix 3.0 disk images in the DART format… which as luck would have it idle cannot mount. However I found another lisa emulator, lisaem ( ) which has a tool to convert the disks from DART to DC42 (disk copy 4.2). So it was a simple matter of converting the disks

lisafsh-tool.exe “Xenix OS Boot Floppy”

… etc etc… ad nasium…

Then firing up idle, setting the CPU to max speed, and booting up whenver I was going to answer a question I toggled it back to 5Mhz.. otherwise it would take FOREVER to boot… lol like the ‘good old days’.

Once the boot floppy had formatted the 5mb hard disk image, and transfered on reboot I had to tell the bootloader to boot from the profile disk..


And away it went. After installing the OS & the C compiler I’m left with 23 blocks free!.. which I guess for a 5mb disk, is pretty cool.. Anyways there are assorted Xenix PDF’s which can be found here:

Namely these two for Apple Lisa Xenix..
It’s amazing that lisa emulators were sort of capable of running Lisa Office System, now they can run the old unix stuff… it’s still impressive.

SIMH 3.8-0 with slirp

Ive been testing this build now for over two hours with Quasijarus & the microvax… All seems well.

The new build of SIMH with SLiRP adds some performance improvements, along with the older more compatable idle code. I’ve included the source with this build so I don’t lose it again… I can’t say just how difficult it was to piece this together again from my notes, and sadly it should have been way easier. The vax/vax780/pdp11/pdp10 are already prebuilt for windows users, and I built them with MinGW… YMMV as they say.

But if you are using one of my prior BSD packages (the 4.2 or the 4.3 RENO) you’ll want to replace the vax.exe/vax780.exe’s with these ones, and alter the config so that they both have

set cpu idle=FIX

that way it’ll run faster, and take up far less cpu when idle… Right now my Quasijarus is using 5% of my laptop idling with 1 connected user.

Quasijarus and other 32v derived tape images

I was looking for a copy of Quasijarus and I noticed that the ftp site is now down. I know it was originally hosted on a VAX, and perhaps it’s met it’s end?

Anyways with a bit of googling I was able to locate a mirror. However since the primary location has already gone offline, I figured this was a good time to go ahead and make tape images for all of the BSD I have at the moment and put it on sourceforge.

I kind of screwed the order up, but you get the idea, you can get 32v-Quasijarus there. The TAHOE stuff is broken on all the mirrors so I haven’t tried to make a tape of it just yet… In the meantime I need to update SIMH 3.8-0 with SLiRP. I’ve been meaning to do it, I just have to force myself as the glue into SliRP is… messy.

Interesting wiki site…

While looking something up, I came across this site:

It’s a wiki dedicated to retro-computing, but more so in first person.. Not so much in the factual history of wikipedia. Anyways I thought it was worth mentioning, and I’ve started to redo some of my work here over there. Hopefully this will get more people interested in the whole thing. I’ve also been thinking about doing a windows installer for the z80 CP/M module from SIMH.. Hopefully the games & stuff work fine, so it’ll be FUN!

Minor SIMH fun

Well I updated the packages for SIMH last night, and I’ve included the win32s stuff and MS-DOS builds. This ought to allow some old schoole to have some fun!

The packages should be visable from here:

I have also decided that the MS-DOS version (being the lowest common denominator) should include some kind of ‘sampler’ of OS’s so that you can see right out of the gate what simh is capable of. Naturally you can download the MS-DOS version, and simply replace the exe’s with stuff for windows/win32s/linux etc..

SIMH 3.8-0 for MS-DOS

This is a quick survey of SIMH 3.8-0 for MS-DOS. I’ve built these exe’s with Watcom C++ 11.0a.

You can break out of any of the simulators by pressing CONTROL+E.

All of the EXE’s are for the MS-DOS environment, and I’ve built them with DOS/4GW in mind. I will have to say that an initial test shows that running this stuff under a DPMI server like Windows or OS/2 provides better performance then native switching.. It could be my PC, however I’d recommend anyone who uses these EXE’s to try them natively and under Windows 3.1 at a minimum.. Because all of the MS-DOS nature of these programs, no disk files can be over 2 gigabytes. I don’t know if that’ll be an issue but of course you can have multiple files/partitions as I recall MS-DOS 5 having a 2 gigabyte file/partition size limit..

For anyone running this natively I have included only one copy of dos4gw.exe in the root of the zip.

1. Altair
2. Altair Z80
3. The HP2100
4. The Interdata 32b
5. The Nova
6. The PDP-11
7. The PDP-8
8. The MicroVAX II
9. The VAX 11/780

1. Altair 8800

This is the Altair 8800 emulator with both AltairDOS and CP/M 2.2

Both CP/M and Altair DOS are from the file


C:\simh\altair\work>altair.exe altdos.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

Altair 8800 simulator V3.8-0


——8<------8<------8<------8<------8<------8< cpm.bat ——8<------8<------8<------8<------8<------8<
C:\simh\altair\work>altair.exe cpm22.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

Altair 8800 simulator V3.8-0
62K CP/M VERSION 2.2 (ALTAIR 8800)
Simulation stopped, PC: 172052 (JNC 172047)
sim> q
——8<------8<------8<------8<------8<------8< ============================
2. The Altair 8800 z80 emulator.

This is more full featured then the other Altair emulator, and I’ve found the z80 to have more
software available. I’ve included the CP/M 2.2 that I found


C:\simh\altairz8\work>altairz8.exe cpm2.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

Altair 8800 (Z80) simulator V3.8-0

64K CP/M Version 2.2 (SIMH ALTAIR 8800, BIOS V1.25, 2 HD, 15-Jan-07)

Simulation stopped, PC: 0F3FA (RRA)
sim> q
——8<------8<------8<------8<------8<------8< ============================
3. The HP2100 emulator.

I really don’t know much about this machine, but I included a way to run the basic1 program I
found online. It kind of reminds me of the ROMBASIC back ‘in the day’… It’s basic with line
numbers so I know it’s kind of old.. I really don’t know much otherwise about this machine.


C:\simh\hp2100\work>hp2100.exe basic1.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

HP 2100 simulator V3.8-0


Simulation stopped, P: 17436 (JMP 17435)
sim> q
4. The Interdata 32b emulator


Both of these unix’s were taken from the files and respectively.

This is research Unix v6 ported to the Interdata. I set the batch file to tell you how to
bootstrap the system, as it doesn’t just ‘turn on’.. Otherwise it should be comparable to Unix v6 on the PDP-11 or any other v6. This should be the first port of Unix outside of Western Electric. There is no halt/reboot/init 0, so I just sync the disk a few times, and then interrupt the emulator and quit.

C:\simh\id32\unix6>id32.exe v6.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

Interdata 32b simulator V3.8-0
at the ? prompt type in:
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

Interdata 32b simulator V3.8-0
v6.ini> d lfc tps 100
Read only argument
Memory = 182.50 K

login: root
You have mail.
# sync
# sync
# sync
Simulation stopped, PC: 2EB5C (EPSR R1,R0)
sim> q

This pretty much follows in the steps of the Unix v6 above. This is the research version of UNIX v7.

At the : prompt type in
ECHO is off.
Then at the # prompt hit CONTROL+D
the root password is root
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

Interdata 32b simulator V3.8-0

: dsk(1,0)unix
Memory = 248.0 K
# Restricted rights: Use, duplication, or disclosure is subject
to restrictions stated in your contracts with Western Electric
Company, Inc. and the University of Wollongong.
Fri Jan 2 18:15:04 EST 1970

login: root
# sync
# sync
# sync
Simulation stopped, PC: 00D20 (EPSR R1,R0)
sim> q
——8<------8<------8<------8<------8<------8< ============================
5. The Nova emulator


This is RDOS V7.50, which I honestly don’t know anything about… I retrieved this OS from the archive rdosswre.tgz .


C:\simh\nova\work>nova.exe rdos.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

NOVA simulator V3.8-0


NOVA RDOS Rev 7.50
Date (m/d/y) ? 10/31/77
Time (h:m:s) ? 10:10:00

6. The PDP-11 Emulator


This is the Unix v1 restoration project’s latest disk image, that I have retrieved from
Being one of the first versions of Unix it’s super primitive, however I thought it was interesting to include in this SIMH sampler to see just how far UNIX has progressed, and just how much is the same.


C:\simh\pdp11\unixv1>pdp11 simh.cfg
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

PDP-11 simulator V3.8-0
Disabling CR
Disabling XQ
RF: buffering file in memory
TC0: 16b format, buffering file in memory
simh.cfg> att dci 5555
File open error

:login: root
Simulation stopped, PC: 007332 (MOV (SP)+,25244)
sim> q
RF: writing buffer to file
7. The PDP-8 Emulator


This is the PDP-8 emulator with OS8. I really don’t know anything about this other then the
‘list’ command… I retrieved this from the file os8swre.tgz .


C:\simh\pdp8\work>pdp8 os8.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

PDP-8 simulator V3.8-0
RX: buffering file in memory

8. The MicroVAX II Emulator


This is the MicroVAX II emulator with a miniroot of Quasijarus 0c. It’s not exactly fully functional in this state, but it’s enough to exercise the emulator, and boot up from disk.
I’ve configured the NVram so it will just boot up by default. I have left the installation tape image as quas.tap. Please note that this is *NOT* enough for a full install, this is just a demo to check that your system works.


C:\simh\vax\quas>vax.exe quas.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

VAX simulator V3.8-0
NVR: buffering file in memory
Loading boot code from ka655x.bin

KA655-B V5.3, VMB 2.7
Performing normal system tests.
Tests completed.
Loading system software.


loading boot

: /vmunix
326312+104440+130352 start 0x23b8
4.3 BSD Quasijarus UNIX #3: Sat Feb 14 20:31:03 PST 2004
[email protected]:/nbsd/usr/src/sys/GENERIC
real mem = 33521664
SYSPTSIZE limits number of buffers to 80
avail mem = 31697920
using 80 buffers containing 655360 bytes of memory
MicroVAX 3000, ucode rev 6
uda0 at uba0 csr 172150 vec 774, ipl 15
uda0: version 3 model 3
uda0: DMA burst size set to 4
ra0 at uda0 slave 0: ra81, size = 891072 sectors
dz0 at uba0 csr 160100 vec 300, ipl 15
dz1 at uba0 csr 160110 vec 310, ipl 15
dz2 at uba0 csr 160120 vec 320, ipl 15
dz3 at uba0 csr 160130 vec 330, ipl 15
Changing root device to ra0a
Automatic reboot in progress…
Tue Feb 3 17:52:10 PST 2004
Can’t open checklist file: /etc/fstab
Automatic reboot failed… help!
erase ^?, kill ^U, intr ^C
# sync
# sync
# sync
Simulation stopped, PC: 800029AF (BNEQ 800029C6)
NVR: writing buffer to file
9. The VAX 11/780 Emulator


The VAX 11/780 is a bit weird in that it cannot run it’s vmb.exe directly, unlike how the
MicrovaxII can run its ROM. I’ve been using extracted boot code to get the 11/780 to run. Again because I’m more familiar with Unix, I chose to include BSD 4.2’s miniroot to test functionality. This is really only suitable for testing the emulator out. I extracted the file bootra from the source code, and I took the miniroot file from the tape.


C:\simh\vax780\work>vax780.exe bsd42.ini
DOS/4GW Protected Mode Run-time Version 1.97
Copyright (c) Rational Systems, Inc. 1990-1994

VAX780 simulator V3.8-0
loading ra(0,0)boot
: ra(0,0)vmunix
4.2 BSD UNIX #9: Wed Nov 2 16:00:29 PST 1983
real mem = 8384512
avail mem = 7073792
using 102 buffers containing 835584 bytes of memory
mcr0 at tr1
mcr1 at tr2
uba0 at tr3
hk0 at uba0 csr 177440 vec 210, ipl 15
rk0 at hk0 slave 0
rk1 at hk0 slave 1
uda0 at uba0 csr 172150 vec 774, ipl 15
ra0 at uda0 slave 0
ra1 at uda0 slave 1
zs0 at uba0 csr 172520 vec 224, ipl 15
ts0 at zs0 slave 0
dz0 at uba0 csr 160100 vec 300, ipl 15
dz1 at uba0 csr 160110 vec 310, ipl 15
dz2 at uba0 csr 160120 vec 320, ipl 15
dz3 at uba0 csr 160130 vec 330, ipl 15
root on ra0
WARNING: should run interleaved swap with >= 2Mb
erase ^?, kill ^U, intr ^C
# sync
# sync
# sync
Simulation stopped, PC: 8000162E (BRB 80001620)
——8<------8<------8<------8<------8<------8< The entire source is in the ‘source’ directory with projects for all of the SIMH material.
There are a few emulators that *WILL NOT BUILD* for MS-DOS because of a lack of 64bit integers. I suppose if there is any call for the missing emulators with the DJGPP compiler, assuming that it contains 64bit integer support. It’s completely unverified on my part. I’ve also done some preliminary work on networking with packet network drivers, however I am experiencing some weird timeouts. It’s hard to track down at the moment, but I’ll keep plugging away.

I don’t think there is any reason why you would not be able to use OpenWATCOM to build these files.