First ... If the following is already known or incorrect then apologies.
In my efforts to get an 11/94 running with UniBus cards the following
came to light.
1. You need to start with the fact there are _two_ different types of
hybrid Uni/Qbus back planes that can go in a BA box.
2. One has _four_ QBus slots and the other _three_.
3. The four slot type was the first type produced .
4. In an 11/84 a four Qbus slot backlane has a MDM (monitor) module in
the first slot, a KDJ11-B CPU in the second slot, PMI memory in the
third and a MLM (load module) in the forth.
5. This type of 11/84 could be converted into an 11/94 with a kit of
parts. The 11/94 manual shows this conversion
6. After conversion you ended up with a KDJ11-E in the first slot, and
an APS module in the second slot.
7. If the 11/94 manual is correct then the other two slots are left
empty and an MLM module is located in the Unibus back plane.
8. So far so good. An 11/84-A converted into an 11/94 as per the 11/94
manual.
Then the weird bit There's a section that mentions an 11/84-E (never
heard of those) conversion to 11/94 but does not seem to make any sense.
So what about the three QBus slot back plane?
Well I have two 11/94 systems with this type of back plane and they are
clearly only suitable to hold an KDJ11-E and its APS module.
It could never be the basis of a KDJ11-B 11/84 - not enough slots.
So there can be two types of 11/94.
One an upgrade from a KDJ11-B 11/84 with its four QBus slot back plane.
The other native KDJ11-E 11/94 based on the three slot.
Comments and confirmations please
Rod
--
Wanted one pdp-8/i rocker switch leaver to copy.
