[COFF] GE-635 GECOS?

[Jeffrey Johnson via COFF]

I should add that we are desperately seeking GCOS-3 and GCOS-8 total system
tapes or any backup tapes.

The DPS8M simulator can be easily adapted for GCOS-3, although we would
need to work on the FNP/FEP emulation specific to GCOS.

For GCOS-8 (and also CP-6) we would need to implement NSA/VU (New System
Architecture / Virtual Memory Unit / MMU) required by those later systems.
Currently we do not implement it, which limits us to GCOS-3.

While we have extensive NSA/VU documentation, likely more than enough
information to allow for writing an implementation, it’s a non-starter
without any software that uses it or any way to test it.

If anyone can help provide any tapes, please see:
https://multics-wiki.swenson.org/index.php/GCOS#Seeking_Software

On Sun, Mar 29, 2026 at 2:12 AM Clem Cole via COFF <coff at tuhs.org> wrote:

> I have no idea how good the 645 emulations are, but if they support the
> mode switch, then in theory, GCOS should boot if you can find a
> distribution tape.
>
> Sent from a handheld expect more typos than usual
>
>
> On Sun, Mar 29, 2026 at 1:31 AM segaloco via COFF <coff at tuhs.org> wrote:
>
> > Does anyone have a feel for the state of GE-635 emulation and preserved
> > GECOS specimens?  Is it possible in 2026 to spin a 60s GECOS
> > environment in a terminal?
> >
> > - Matt G.
> >
>