7 Feb
2015
7 Feb
'15
3:17 p.m.
From: Jerome H. Fine
With regard to the MSV11-JD in the PDP-11/84, was this
board placed
after the KDJ11-AE board or before it?
After. The CPU _has_ to go in slot 1 on the 11/84 backplane. (I suspect, but
have yet to verify, that this is in part because bus grant lines are run
directly from that slot to the UNIBUS adapter slot.)
Also, has anyone ever used a KDJ11-AC board with the
15 MHz crystal in
the PDP-11/84 backplane? I can't see why it should not work, but just
maybe the PDP-11/84 backplane and a simple KDJ11-AC board are not
compatible.
Would a KDJ11-A board even work in an 11/84 backplane? It wouldn't (couldn't)
do the special PMI (actually, we ought to distinguish between 'QBUS PMI',
such as in the 11/83, and 'UNIBUS PMI', as in the 11/84; the second is a
superset of the first, I believe) protocol, so it wouldn't work with the
UNIBUS adapter.
See also Micronote #39, "Differences between KDJ11-A and KDJ11-B".
Noel