Wondering which OS to use (PDP-8/A)

[Ethan Dicks]

On 10/21/05, charlesmorris at direcway.com <charlesmorris at direcway.com> wrote:
> Now that I have an apparently functioning PDP-8/A with 16K of core, and (hopefully soon) a working RL02, I am wondering what operating system would be appropriate.

In the case of the gear from the 1970s, OS/8 was rather expected.  You
_can_ do all sorts of stuff with paper tape (using a modern machine to
emulate it), but for machine with block-addressable storage (DECtape,
floppy, hard disk), OS/8 was by far and away the most popular.

> Currently I don't have any other input device aside from the programmer's panel
> and the keyboard, so naturally I need something that can be booted from an
> RL02...

You may or may not have an RL boot PROM in your KM8AA, but if you
don't, you can always key in the RL bootstrap by hand.

> Any recommendations? Will software written for, say, an 8/E or 8/I run on an 8/A without patching?

Generally speaking, yes.  The changes to the instruction set are minor
and meant to be additive, but a really clever 8/i programmer can trip
you up.  There's a reason FOCAL does some probes to determine CPU
type.

> Could I run OS/8? TSS/8? Many years ago I used to have access to a TTY timeshared to an 8/E running Edusystem 50 (TSS/8) and would like that "feel" again...

Dunno about TSS/8 on an RL (probably no driver for anything newer than
an RF08), but certainly OS/8.  One caveat - there is a different
driver for the RL01 and for the RL02.  I myself have never used an
RL02 on an 8/a.  An expensive configuration for a DECmate I was an
RL02, so I'm sure OS/78 supports it, but you might have to cherry-pick
your OS/8 version to go with a larger disk.

-ethan