General Question about UNIBUS backplanes
jnc at mercury.lcs.mit.edu
Sun May 22 19:34:06 CDT 2016
> From: Bill Degnan
> So I decided to insert two 32K core memory backplanes
32KW, those would be MM11-U backplanes, right?
> My plan is to replace the solid-state RAM card with core, and this will
> free up a slot on the 4-slot backplane for a terminator.
Terminators all only go in the last slot of the last backplane anyway (either
that, or a UNIBUS 'out' cable), so adding extra backplanes shouldn't give you
"a slot .. for a terminator".
Also, Paul's point is a good one: the hex memory cards need so-called 'MUD
slots' (hex), not SPC slots (quad), and only (IIRC) the DD11-C/D have MUD
slots. (Those came in with the 11/04-34, IIRC).
> the serial card seems to have stopped working. It appears that the
> console program is being loaded and runs from the M9312 but nothing is
> appearing on the terminal. I cannot send an "A" to the terminal, the
> most basic test I can think of.
Hmm. You can read/write the console registers from the console, though, it
sounds like? My guess would be that if your serial port is EIA, somehow
you're missing -15V or something on the DD11 in its new location. Study the
-11/35-40 system manual to learn about which 'bricks' supply which voltages
to which system units.
And while you're at it, check that you have the right 'bricks' for the MM11-U.
The -11/35-40 system manual has lots of text on how to support the MM11-U.
> Can you only use the core backplanes for core memory (assume yes), or
> are they capable of holding other types of cards temporarily?
AFAICR, the MM11-U backplane does _not_ have an SPC slot in it. IIRC, the
16KW MM11-U board set is a quad controller board, and 3 hex boards (core, X-Y
and something else). So two sets (the backplane holds two) would be 8, so one
empty slot - which IIRC is blank. Check the MM11-U manual, it's available.
> I have one slot that needs the npg, it's in place.
??? _Every_ SPC/MUD slot which does not have a DMA device in it _must_ have
the jumper on the backplane (or the _double_ width UNIBUS grant card, whose
number escapes my memory, which contains a NPG jumper). Not sure if that
was the import of what you wrote there.
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