DEC PDP-11/45 backplane +5 ECO

Noel Chiappa jnc at mercury.lcs.mit.edu
Sun Apr 25 22:49:54 CDT 2021


    > I had a look at my /45 ... and it seems to ... look just like those on
    > Josh's. I'd really want to take pictures of mine .. so I can compare
    > them directly, though, not depend on visual memory.

Yeah, mine (a late /55, actually) has the _exact_ same wires at Josh's.
So that's probably the final ECO level. Image here:

  http://ana-3.lcs.mit.edu/~jnc/tech/pdp11/jpg/1145CPUBackPlane.jpg

if you're interested. (Not a great image, but OK; I can try for a better one
if there's a need.)

    > From: Henk Gooijen

    > Most of the CPU boards in the 11/55 are the same as the ones in the
    > 11/45

The -11/45, /50 and /55 are all the same CPU (KB11-A or -D), so the same
backplane/everything, but differ only if they were sold pre-configured with
the MS11 Fastbus memory.

And of course some /45's (especially those sold before the introduction of the
/50 and /55 as sales options - I have a /45 price list from Sep, 1972 which
lists the /45 and /50 but not the /55; and one from Jan, '73 which only lists
the /45 :-) were upgraded (possibly after sale, after the /50 and /55
appeared) with MS11 - or possibly some /50's and /55's had the MS11 removed at
some point. So the number doesn't mean anything; one has to look at the
boards.

	Noel


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