PDP-11

[Noel Chiappa]

    > From: Dave Wade

    > Cards are
    > M7264

11/03 processor with 4-Kword MOS RAM

    > M7940
    > M9400ye

DLV11 Serial Line Unit (system cosole)
REV11-E (240-ohm terminators for Q18)

QBUS termination is a complex subject; when you have multiple backplane
sections, connected by cables, each section has 'termination'. That's what
this REV11-E card is; it's also the QBUS 'out' to the card in the 780 CPU
which the console -11 uses to control the /780 CPU. Why it's in the middle
slot, I'm not sure (unless things have been moved around)?

    > M8044ee
    > m7946

MSV11-?? (My list doesn't contain an '-EE', but it's some sort of
small MOS memory, Q18)
RXV11 (RX01 8" floppy disk controller)

In theory, the M8044-EE should be an "MSV11-DE" (not "MSV11-EE", that would
be an M8045-EE), but none of my documentation, including the M8044 prints,
covers such a variant. Maybe I need to look in the /780 prints, it may be
a special variant for use in the /780 console machines.

    > M8192

LSI-11/73 CPU; a nice machine, if you can eventually get it running. You'll
want a bunch more memory (note that the M8044/8045 cards are Q18, and so you
can only have up to 256KB with them - they _WILL NOT WORK_ in a system with
more than 256KB in it).

    > Also have loose grant card....

You mean an M9047?


I would start with just the 11/03 CPU and the console card; hook it up to
something, and see if you can get it to talk to the console. (Configure
the CPU to halt, and fall into Console ODT, on power-on.)

It's probably worth getting one of the various LSI-11 CPU handbooks:

  Microcomputer Handbook (1976-77)
  Microcomputer Processors (1978-79)
  Microcomputer Processor Handbook (1979-80)
  Microcomputers and Memories Handbook (1981)
  Microcomputers and Memories Handbook (1982)

they all cover the quad-width 11/03 CPU. Although they're probably available
online, it's very handy to have a hard-copy one; those are available on eBay
and such.

That backplane is probably a so-called 'serpentine' backplane, i.e. ones in
which the (dual) slots are numbered:

   1 2
   4 3
   5 6
   8 7

so the console would need to go in '3' if it's the only card other than the
CPU (at least, if you want it to be able to do interrupts).

Once you get it working in that configuration, you can configure and add the
memory card (if you can figure out what the devil it is ;-). And then the
RX01 controller.

The REV-11 isn't needed in this configuration. The boot PROM for this machine
was actually on the card in the /780 CPU, so eventually you'll need a
replacement - something like a BDV11 or something (they are available, and
not too expensive).


    > From: Robert Jarratt

    > The seller said it was indeed out of a 780.

Yeah, that's what it looks like.

    > I got the impression the 11/23 card was just a spare he had that he put
    > in the enclosure, not really part of the original system.

Actually, an 11/73, but yes, definitely not part of the original system. I
don't know if it will work in that backplane without the backplane being
upgraded from Q18; it might, but that would need some investigation.

	Noel