[TUHS] Running Research Unix v3 on simh

Benito Buchheim benito.buchheim at student.hpi.de
Wed Aug 7 17:51:34 AEST 2019

Hello everyone,

My name is Benito Buchheim and I am a computer science student at 
Hasso-Plattner-Institute in Germany.
During our Operating Systems Course we came across The Unix Heritage 
Society, more specifically Research Unix Version 3, and took a look into 
the source code of this version.
The idea arose to try to get this running somehow as a sort of voluntary 

So I started digging my way through the available material and quickly 
found the "modified_nsys" version by Warren Toomey, which conveniently 
contained a very detailed readme file on how to compile and run this 
version on a Unix v5 emulator.
Thus, I started cloning the simh Github Repository and built the pdp11 
After downloading the v5root disk image and figuring out how to use simh 
to run it, I had a working Unix v5, but struggled a bit to copy more 
than one file onto it using the emulated devices.
In the end, I used a very Hacky way and wrote a short python script 
which just runs the emulator and "copy pastes" the folder structure into 
the image. I now thought to be ready to start working my way through 
Toomey's readme.

Unfortunately already the first command failed quite miserably. I 
changed my working directory and ran the first shell script to compile 
the kernel, but cc spat out loads of error messages which are not very 
detailed. As this is a very early version of c code I am kinda stuck at 
this point and running a bit out of ideas on what may have gone wrong.
As there is this mailing list we thought to have a chat with the 
experts. Maybe there is somebody who could help or give a hint on how to 
get this running on the pdp11 emulator.

I attached my shell script output and the v5 image containing the v3 
source code in the /sys/nsys directory.
It can be downloaded here:

Thanks a lot and best wishes from a small suburb near Berlin,
Benito Buchheim

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