PDP-11/05-NC with M9301?

Noel Chiappa jnc at mercury.lcs.mit.edu
Thu Mar 17 07:49:11 CDT 2016

    > From: Mattis Lind

    > I was thinking of using a M9301 board to get a console emulator and
    > some different bootstraps with the 11/05. But can I just put the M9301
    > in the slot where the M930 normally goes?
    > ...
    > M9301 goes into MUD slots. But can it go into the slot where a M930
    > normally sits?

I haven't personally looked into doing this in detail, so I can't give a
definitive answer, but your last question here makes alarm bells go off in my

The M930 is designed to go in UNIBUS In/Out slots. These slots do have
different wiring from the A/B MUD slots. (For instance, UNIBUS In/Out slots
have _single_ pins assigned for BG4-7 and NPG, providing 'grant in' or 'grant
out' functionality, depending on if it's an In or Out slot. I don't recall
offhand what function/signal is on those pins in a MUD slot, but I'm pretty
sure it's not a grant!)

I would be fairly astonished if a device intended for a MUD slot would work
in a UNIBUS In/Out slot, and vice versa.


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