KT-24 and/or -11/24 backplane info

Noel Chiappa jnc at mercury.lcs.mit.edu
Sat Jul 30 17:51:54 CDT 2016

    >> I guess it will require getting ahold of a backplane, and seeing what
    >> I can find out with an ohm-meter.

    > It looks like I'll still have to do this at some point, to confirm my
    > theories about how the two busses are wired on the backplane
    > (separation of UB and EUB address lines, and cross-connection of the
    > data lines, for the EUB/SPC slots)

I have checked an -11/24 backplane, and the wiring is indeed as I
hypothesized (above).

    > Another mystery: The "PDP-11 UNIBUS Processor Handbook" (1985) says
    > (pg. 4-10) that in the 5.25" box, "only one MS11-P memory module can be
    > configured". Anyone know the cause/source of that restriction?
    > ... 
    > I can't come up with any technical rationale for that limit? Am I
    > missing something? Or is it just DEC marketing, trying to limit how
    > powerful the machine can be?

I would still be grateful for any insight from anyone about this.


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