Able board on eBay

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri Mar 3 10:34:24 CST 2017


    > It's one part of a DMAX/16.

Oooh, good catch. I hadn't looked carefully at those faint images, I was just
looking at the brochure which had the separate images.

    > Not nearly as cool as an Enable :).

Yes; the ENABLE was pretty clever: it used an MUD backplane as an EUB
backplane, to hold the ENABLE and stock EUB memory cards; both the CPU _and_
DMA devices were on the incoming UNIBUS, and the ENABLE could tell whether a
read-write cycle was from the CPU, or a DMA device (if you look at the UNIBUS
spec, there's just enough to do that, even without being able to see NPG), and
routed it through the appropriate mapping, depending.

       Noel


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