12 Dec
2005
12 Dec
'05
11:01 p.m.
Subject: Re: PDP-11/73 booting!
From: Pete Turnbull <pete at dunnington.plus.com>
Date: Mon, 12 Dec 2005 22:01:12 +0000 (GMT)
To: "General Discussion: On-Topic and Off-Topic Posts"<cctalk at
classiccmp.org>
OK, but that would be unusual, and not exactly standard :-) Was that
a protoype?
Nope. Early production with 11/23B orginally. If you have/had a BA23
DD and printset you find there are a lot of variations some are just
mainline and some for specific customers. for example the LS-spec
stuff for TELCO.
You could certainly use Q22-CD slots for
11/23-compatible
memory -- yes, I know the microPDP11/23 is just a KDF11-B with
different ROMs -- and I've never seen a BA23 that wasn't 3 x Q22-CD
plus 5 x Q22-Q22, which is what the tech manuals and maintenance
manuals I have describe. I don't even know of any other 4 x 8
backplane that could fit.
Actually there are three that fit and two with the right connector
(molex style pins). the CD slots mean nothing if your using quad
width memory but it's a big differnce if your using dual width.
Well if you started with a fully-serpentine Q22-Q22
backplane, the
microVAX memory would need it changed, because the cards talk to each
other using the CD-interconnect, which I'd forgotten (but not AFAIK for
CPU/memory transfers, which are over the top). The front panel,
though, is the same except for the badge, everywhere I've seen. The
console/SLU panel, the *back* panel, is different, of course.
uVAX-II and 11/73B need/require over the top. 11/23B (and 11/73A)
is strictly Q22. I happen to have the earlier non-pmi 11/73.
And of course the uVAXII.
Allison