Unibus disk controller with modern storage
jnc at mercury.lcs.mit.edu
Thu Oct 20 16:32:07 CDT 2016
> From: Paul Koning
> That's fine if your target is an OS for which you can write drivers. It
> wouldn't help RSTS users.
Right, they're stuck with exact clones of DEC controllers. (For Unix, tweaking
the RP11 driver to handle the extended RP11 should take all of 12 minutes,
> Q22 disks .. RL02 also, if I remember right.
Oh, right, the RLV12 - forgot about that. Still, it would be nice to be able
to run RK11's and RP11's in 22-bit mode! :-) Especially since there will be
replicas of DEC's indicator panels for them, whereas an RL11 indicator panel
would definitely be... an anachronism! ;-)
> A possible answer for a lot of this is to do the actual emulation
> algorithms in software, in an embedded CPU inside the FPGA. For MSCP
> that's obvious, but it would work for the others as well I suspect.
Dave B is a wizard with Verilog, so until it gets to the complexity level of
MSCP we'd probably do it all in Verilog.
> From: Jon Elson
> I did **ONE** board with some kind of gold flash that a PCB house
> recommended. ... it was a colossal disaster. You had to lift the pin
> ... Since then, I have used pure tin HASL, and had little trouble.
I think gold came into the discussion in the context of the contact fingers
where the board plugs into the backplane. I've never seen a QBUS/UNIBUS board
with tin fingers, although they were common on SIMM memory cards; no idea
if tin would work for QBUS/UNIBUS - although now that I think about it,
SIMM cards didn't slide into position, but kind of rotated, so maybe tin
would work there.
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