[Unix-jun72] Semi-OT: Other systems to reconstruct?

Andrew Warkentin andreww591 at gmail.com
Thu May 22 13:05:09 AEST 2008

With the successful restoration of Unix V1, I was thinking of other
operating systems that could be restored in a similar way. The most
historically significant would probably be CTSS. The SIMH IBM 7094
simulator has everything necessary to run CTSS implemented already,
although the CTSS-specific stuff is untested (since as far as I know,
nobody has booted CTSS in it yet) and may need some patching.

There are several tapes of listings (for almost all of the system), and
a few tapes of binaries (one with supervisor binaries, and one with
"standalone" utilities, but nothing with user-mode programs) available.
The listings need to be converted back into source that can be assembled
or compiled. Part of this can be done automatically (I have written some
dumb scripts to do this), but there will likely be quite a bit of manual
editing involved. There is nothing to be OCRed, since everything is on 

Most of the source is either assembly or MAD (an Algol-58 dialect), with
a few files in AED (another Algol dialect, for which no compiler appears
to have survived). Restoring the assembler stuff should be easy (there
exists a cross-assembler which would work), but restoring the MAD stuff
will be a little bit harder. There is no cross-compiler for it (there is
a compiler that runs under IBSYS, but it is probably just for an IBSYS
target, and I'm not sure if anyone has even figured out how to run it).
The AED stuff will have to be rewritten in MAD (which shouldn't be
especially hard, since AED and MAD are somewhat similar). Only a few
non-essential programs are written in AED.

I think that all (or at least most of) the stuff required for booting is
written in assembler, so the best way to get it working would be get a
minimal system booting (I suspect all that is necessary is the
supervisor, so the binaries on the tape might be of use), and run the
CTSS MAD compiler under it to compile all the MAD stuff (which includes
many of the "core" commands).

I'm not sure what the best way to get stuff into a filesystem is. The
standalone utilities run under FMS, and there is no bootable FMS tape.
There is a version of FMS that runs under IBSYS, but for some reason, it
  returns an error when attempting to load the utilities off the tape.
It  is probably possible to patch it to fix that bug, though. It would
also work to write utilities that run on the host system, much like what
was done for Unix V1 (although I think that fixing the bug in FMS would
probably be easier).

Maybe I should start a Sourceforge project.

Another, much simpler, system which might be possible to restore is
MUMPS-15, for which a PDF of a paper listing is available on bitsavers.
Restoring it would probably just be a matter of OCRing, correcting, and
assembling it (and maybe writing a bootstrap).

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