[Simh] PDP-8: The possibilities?

[Ethan Dicks]

On Thu, Sep 8, 2016 at 8:04 PM, Davis Johnson <davis at frizzen.com> wrote:
> I've always been fascinated by the PDP-8S, in part because of the great
> story behind it. I keep seeing references to it not being 100% compatible
> with the other PDP-8 systems. How different was it (or how was it
> different)? Is there any 8S specific software extant?

The only thing I can thing of is FOCAL knows about all the variants,
including the -8/S and does "the right thing".  I don't know of code
written for the -8/S and only the -8/S.  Mostly, everyone was trying
either to be inclusive of several models, or the specific model they
were writing for, or, eventually, just the OMNIBUS models without
going to any lengths to work with the pre-OMNIBUS models.  It kind of
depends on when the code was written and if the code was planned to be
shared outside of the place it was written.

ISTR the first 3 models (PDP-5, Straight-8, and PDP-8/S) were the
least like later models and dropped off the table first.

I started with the PDP-8/L, so much of my focus is finding stuff that
reaches back at least that far.  I also care about the oldest models,
but I think the biggest "split" is OMNIBUS or pre-OMNIBUS.

-ethan