Unibus questions

From: Doc Shipley <doc_at_mdrconsult.com>
Date: Wed Sep 24 14:28:31 2003

   I'm going over the card configuration of a PDP11/84 and reading the
online documents, and I'm confused about a couple of things. I need to
get squared away on this, as I'm testing some drives needed in
production and only have Unibus SDI adapters.

   Pardon the obvious lack of clue. I've never worked with a Unibus
machine before, and don't know the terminology at all. Also, I have a
hand-written diagram from someone even less educated than I, so if there
isn't a board number with the description, I don't have it or can't
clearly read it. I won't physically see the machine till this weekend.

   First, there's an expansion chassis. It has a terminator card
(M9302) in row 7 (starting from 0) in what I assume is slots E-F (front
of the rack is A?). OK, I get that, but theres a non-NPG single-slot
grant card in row 7 slot C, and in succeeding rows, there are more
boards - M9700 or M9100, M105, M7226 in row 8, power and M7821 in row 9,
power and M117 in row 10, and M002 in row 11. How is this functional?

   Is there a reliable way to determine grant configuration without
physical examination of the backplane? The machine was [allegedly] very
recently running in this configuration, but I don't want to smoke
something by counting on that. I'd like to strip the non-essentials for
testing. A test setup in a single card cage - base boards plus SDI and
RX02 controllers - would save a lot of juice and reduce points of failure.

   Last, the CPU is an M8190-AE, which lists in Megan Gentry's reference
as 11/84 *or* 11/83? So I could drop this pup into a QBus chassis after
the SDI drives are tested? What would be the relative merits of doing that?

Received on Wed Sep 24 2003 - 14:28:31 BST

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