PDP 11/23 help needed

From: Seth J. Morabito <sethm_at_loomcom.com>
Date: Wed Apr 22 02:16:41 1998

Well, folks, it looks like I lied in my recent post about not having
a PDP-11.

Actually, I _do_ have one. I simply forgot that I had, stashed
away, an 11/23 CPU and some boards ("common as houseflies" was the
term Allison used? :> ) Since it was not in a rack, and since
the pieces have never been assembled, and since I have no disks for
it, I pretty much forgot about it, and I've never had it working.

But it appears I have a fairly nice, complete system, board-wise.

Here's what I have:

-----
Chassis: DBA11-N
Cards:
1. M8186 (KDF11-AA) 11/23 CPU with KTF11-AA (MMU), sockets for FP11
2. M8047-CA (MXV11-AC) 16-Kword RAM, 2 async EIA SLU, w/ 2 24-pin ROMs
3. M8047-CA (MXV11-AC) 16-Kword RAM, 2 async EIA SLU, sockets for ROMs
4. M8044-DB (MSV11-DD) 32-Kword 16-bit MOS RAM
5. M8044-DC (MSV11-DD) 32-Kword 16-bit MOS RAM
6. M7269 (RKV11) RK05 controller
7. Data Systems Design 818836-01 REV B -- RX01, RX02, or RX50 controller??
   (25-pin ribbon-cable connector)
-----

So, in order to get this whole thing working again, I have a
WHOLE SLEW of questions to ask folks, in no particular order.
Here goes.

1) The M8047-CA boards need to be wire-wrapped to assign their
    address vectors -- they're combination MOS RAM and Async EIA,
    and I have no docs for them. Can anyone guide me to some info,
    or tell me how to jumper one of them to be console serial
    port, and the other to be next in line on the bus?
    The wire-wrap pins have absolutely no markings on them, not
    even any single-letter or number labels, so this one could
    require ASCII-art to describe :)

2) Same as above, but for the M8044-DB boards. I could put one
    of these in with the M8047's to get a full 64Kword of RAM, yes?
    Does anyone know what the DIP-switch settings for these boards
    are?

3) I'd love to have the RK05 controller in there, in the hopes
    that someday I'll have an RK05 to play with. Just like the
    above... How do I jumper it, and where (physically) in the
    Bus should I put it?

4) Actually, that raises a good question. All of these boards
    are single-height (1/2 the width of the Q-bus backplane).
    I know there is some special physical layout the boards should
    use when they populate the backplane, but what is it?
    My best (probably wrong) guess right now is:
      CPU in row 1, slot 1 (is that left or right?),
      M8047's in row 2, slots 1 and 2,
      M8044 in row 3, slot 1,
      M7269 in row 4, slot 1, DSD controller in row 4, slot 2.
 
    Does that make any sense? Should the CPU only live in the
    first row, not RAM? I seem to remember something like this
    from the darkest depths of my mind, but I don't remember
    for sure.

5) OK, simple question, one I've wondered about but never bothered
    getting answered because I felt like a complete idiot moron
    asking it: Does the QBUS need to be terminated by a special
    card in any way, in order to work?

6) What's the pin-out on the M8047 EIA ports? They're 9-pin Berg
    connectors, and I need to build a cable for them to connect
    either to 9-pin or 25-pin PC-style serial in order to set up
    any kind of console terminal.

7) Anyone know what the Data Systems Design board is? It has
    "RX" stensiled onto the board near the jumper block, among
    other things like "BOOT", so I assume it's some sort of RX01
    or RX50 controller or some such.

WHEW, that's _too_ many questions. Anyone who can tackle one of them
gets my respect, and you may award yourself one cookie.

I'd like to piece this system together and get it working to the
point where I can play with it and at least fiddle with the monitor
again, playing with Octal. And I'd dearly love to put it in a
proper DEC desk-side rack with an RK05, but that comes later...

Thanks much,

-Seth
Received on Wed Apr 22 1998 - 02:16:41 BST