UNIBUS PDP-11 memory expander card

Noel Chiappa jnc at mercury.lcs.mit.edu
Wed Jan 28 14:06:23 CST 2015

    > From: Jacob Ritorto

    > I just happen to have one in my hand as we speak. I'll photograph it...

Hmm. That photo (here:


if anyone wants to see it) shows a very different card than the one in
the brochure. That one's a hex card, with an over-the-back connector:
this one's quad, no OTB connector.

This looks more like a QNIVERTER?

Does it say 'ENABLE' on it anywhere? (Which would imply there was more
than one variant... which would be interesting, because I have this bit
set that the one we had at MIT was not like the one described here:


because I'm pretty sure that on ours, the DMA devices were on the far side of
the ENABLE - which makes sense, because ours had separate PARs and UNIBUS map
registers, which make no sense in that configuration - unless Mike [blessings,
wherever you are] made a mistake in drawing that up.)


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