[TUHS] PDP-7 Unix Progress

Warren Toomey wkt at tuhs.org
Tue May 3 17:21:55 AEST 2016

All, a status update on the PDP-7 Unix restoration project at

The system is pretty much complete now. We have as much of the original
code working as we can. We have rewritten things like the shell and some
other utilities (ls etc.). The ed editor and the native assembler both
work. We also have written a user-mode PDP-7 simulator to test things
and an assembler to make building things faster.

The system boots up under SimH with a filesystem and you can see what things
were like back in 1970.

One big missing utility is roff. As of today, I've written a compiler that
inputs a vaguely C-like language and outputs PDP-7 code. Using this, I've
compiled a minimalist roff which is enough to format man pages. This is
a separate project here: https://github.com/DoctorWkt/h-compiler

Now we are hoping to get the Living Computer Museum people to bring it up
on their real PDP-7. Unfortunately, it doesn't have a disk drive. The
expected solution is to build a disk simulator with an FPGA and SD card.
There is no time frame for this, but it is in the works.

Thanks go to Phil Budne and Robert Swierczek for all their hard work
in building and testing things, and also to Norman Wilson for supplying
scans of the original documents.

Cheers, Warren

More information about the TUHS mailing list