Building a PDP-11 for the first time

From: Eric Smith <eric_at_brouhaha.com>
Date: Fri Dec 12 15:12:47 2003

> The issue is that there's NO SUCH THING as an 11/84
> cpu card, since 11/84 systems use an 11/83 (ie qbus)
> cpu

There most certainly IS an 11/84 CPU card. It happens that it's
the same module as an 11/83 CPU card. They're both the KDJ11-B
(M8190).

When plugged into an 11/84 system, the KDJ11-B does NOT use Qbus.
It uses a unique bus that is similar to Qbus, but has some significant
differences. Also, the PMI (Private Memory Interconnect on the C/D
edge connectors) in an 11/84 behaves a little differently than the PMI
in an 11/83.

> with a Qniverter to convert to UNIBUS.

It's a KTJ11-B (M8191). It's not a Qniverter, or even similar to
one. It is not capable of converting Qbus to Unibus (or vice versa).
It ONLY works with the special CPU bus in the 11/84 and 11/94.

The 11/84 uses MSV11-J memory. The MSV11-JB (M8639-Bx) and
MSV11-JC (M8639-Cx) variants will ONLY work in an 11/84 but not in
normal Qbus or Qbus/PMI systems. The MSV11-JD (M8639-Dx) and
MSV11-JE (M8639-Ex) will work in either kind of system.
Received on Fri Dec 12 2003 - 15:12:47 GMT