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@rileyriot.com



On Mon, 28 Sep 2020 at 04:51, Noel Chiappa <jnc@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
>