[TUHS] Can PDP-11/23 PLUS run Unix?

[Noel Chiappa via TUHS]

    > From: Matt Gilmore

    > If there's not an out-of-the-box solution already, this paper may be
    > useful in re-porting V6

Not quite "out-of-the-box", but there are detailed instructions on how to
bring up V6 on a /23:

  https://gunkies.org/wiki/Running_UNIX_V6_on_an_-11/23

That page was prepared after actually doing it on actual hardware, so there
are no not-yet-seen tarpits (note the reference to "has been observed to
trash the disk, if you are really unlucky").

I suspect the biggest obstacle is likely to be getting the bits onto whatever
the OP is using for mass storage (I see a reference to "QBone to emulate
memory", but whether "memory" there refers to 'main memory' or 'mass storage'
I'm not clear on, although the later "emulate up to 4 Mb of memory" makes me
think the former might have been meant; I'm not familiar with the QBone).

You do need the KTF11-A memory management chip to run anything other than
MINI-UNIX or LSX, but I think all -11/23 Plus systems have it.


    >> I need to know if Floating Point support is a requirement as well

Not required; "if it has a KEF11-A floating point chip, [a small amount of ]
additional work is needed to allow its general use, since the -11/40 did not
support FP11 floating point, and so there is no code to handle it in m40.s."

    "if I can also emulate up to 4 Mb of memory

"All -11/23's after the (very rare) model A can support more than 256KB of
main memory. If you put more than 256KB on an -11/23 and boot V6, it will
ignore the extra memory above 256KB (technically, above 248KB)." but it's
simple to allow use of more (see the instructions, for how).


    > From: Robert Myers

    > Can Mini-Uniz run on a 11/23 Plus?

It should; I got it to run on an -11/03. See:

  http://ana-3.lcs.mit.edu/~jnc/tech/unix/Mini/Mini.html

but there's no point if you hsve a KTF11-A.

	Noel