What quad QBUS boards work in a Q/CD backplane? - test-drb@ccmp.vtda.org

30 Sep 2014

...
 Noel Chiappa wrote: 
...
 Does anyone know of a list of quad QBUS cards that work
(or do not work) in
Q/CD backplanes (other than the board pairs specifically designed to go in a
Q/CD backplane, of course)? I tried Google, but either there is no such list,
or my Google-fu is pretty weak.

For instance, I'm looking at a BDV11, and it has the usual grant jumpers on
CM2-CN2 and CR2-CS2, but I don't think those will be a problem (provided there
is no quad board immediately next to it). Similarly, CB2 is tied to DB2, and
the two feed (through a jumper which is normally removed) special power (-5V)
for a particular kind of EPROM; but again, I don't think this will be a
problem (again, if blank neighbour slot).

But I'd rather not have to go through that exercise for every quad card; it
would be nice if there's a table which just says which ones are OK. (I did
find mention, in the 1980 Interfaces Handbook, in the BA11-N entry, that
MMV11-A modules will _not_ work in a Q/CD backplane, which _implies_ that
all the rest are OK, but...)
 I don't have a list, but there is at least one example of "do not
work" for
the RL01 / RL02 Qbus controller which uses a 2 board set and supports
ONLY 18-bit.  The M8013 / M8014 requires that BOTH boards be
(probably adjacent) in two quad Q / CD slots.  Placing the boards into
 a Q / Q backplane will release the magic smoke.

While not a good example, in a BA23 box, place the CPU board in the
first slot with the M8013 / M8014 in the second and third slots.  The
non-PMI memory and the other boards will then occupy the other 5 slots.

PROBABLY (as mentioned in other posts), the Qbus PMI memory must
also be used in a Q / CD backplane AND in this case placed above the
CPU board, in this case an M8190.  On the other hand, if the PMI memory
is placed below the CPU board (but still in a Q / CD slot), then the memory
will still function correctly, but NOT as PMI memory.

Contrary to what is stated elsewhere, the M8190 boards which support
the use of PMI memory work (as far as I understand - I have done so on
a VT103 which uses a Q / Q backplane) with either type of backplane,
although obviously with the Q / Q backplane, NEVER use PMI memory
in the first place.

Jerome Fine