29 Sep
2020
29 Sep
'20
7:20 p.m.
Noel,
Regarding the boards, the non-DEC one is the 16kW board I bought installed
in the '03, so I guess that works fine.
I managed to follow instructions for SimH and install and configure a V6
system. Was quite satisfying, and was quite an education. So many lessons
in one session, a really good exercise.
I'm checking with Peter Schranz about whether or not his RLV12/RL02 boards
can run on the '03. May be a similar issue with knobbling some of the pins,
if I'm lucky.
*Paul Riley*
Mo: +86 186 8227 8332
Email: paul(a)rileyriot.com
On Mon, 28 Sep 2020 at 04:51, Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote:
From: Paul
Riley
I also have a DEC 256KB board, but I doubt I
could use it on the
'03.
Yes, DEC 256KB boards are what's called Q22, and those don't seem to work
with
LSI-11's; not even CPU ODT works. I just tried a 256KB MSV11-L with an
LSI-11,
and it definitely doesn't work; the MSV11-P is definitely a Q22 board, and
so
probably also won't work.
What the Q22 means is that early in the lifetime of the QBUS, it only had
18
address line - so-called Q18. (Technially the LII-11 used only 16 address
lines,
so it's actually Q16.) DEC latter snarfed some of the 'unused' pins, and
made them QDAL18-21. So boards that use those pins for QDAL18-21 are 'Q22'
boards.
My theory on what the problem is is that the LSI-11 uses some of those pins
for other things - I think the 'run' light, IIRC. So that confuses Q22
memory.
If one tries to use one with an LSI-11, the machine is totally dead - not
even
ODT. It doesn't do any harm, though; unplug the Q22 memory, and plug in a
Q18
card like an MSV11-D, and it'll be fine.
If you need memory for the LSI-11, MSV11-D boards are pretty common on
eBait,
for not much. They tend to be flaky, though; sometimes they come back to
life
if you leave them sit for a bit after you plug them in.
I believe the [memory] board is non-DEC.
Well, if it's Q22 it won't work either. Both that and the DEC board should
work in the /23, though. (If you have the part number on the memory chips,
a
little arithmetic should give you the board size. 256K and up are
generallly
Q22; if you have a manual for that card it might say.)
I'm still working with Mini-Unix; it's very fragile. When I got it running,
the first thing I tried to do was changle the line editing characters
(since
my normal ones are burned into ROM). Alas, in stock V6, DEL is hard-wired
to
be 'interrupt process', so I can't just 'stty [mumble]', I have
to rebuild
the
kernel to change that. Not a problem, necessarily - but I edited tty.h and
said 'cc -c tty.c', and it crashed and re-started - and roached the disk.
So
I'm still trying to make progress. I might have mis-configured the
simulator,
I'll see.
Noel