>> 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. Noel