[rescue] New to me PDP-11/23+

Ron Pool amp1 at cornell.edu
Tue Oct 11 14:55:13 EDT 2022


John Wilson has the schematic and design files for making up a cable that’ll work with KDJ11-B (and some other DEC CPU boards and DLV11-J SLUs) here: http://www.dbit.com/wilson/dlvdb25/

Glitch sells pre-made cables on Tindie for $10 each: https://www.tindie.com/products/glitchwrks/dlvdb25-dlv11-j-rs-232-adapter-cable/

                                 -- Ron
--
Ron Pool
Computer Center / CALS IT Geneva
Request IT help: http://help.cals.cornell.edu/

From: rescue <rescue-bounces at sunhelp.org> On Behalf Of Steve Hatle
Sent: Tuesday, October 11, 2022 2:46 PM
To: The Rescue List <rescue at sunhelp.org>
Subject: Re: [rescue] New to me PDP-11/23+

Thanks everyone - all good info!

Unless I'm missing something, my board only has one SLU - J1. J2 is a 20 pin connector and would be used to bring out the DIP switch settings, etc. If there's another 10-pin hiding on there, I missed it, and the board is not handy to double-check. Also, see the pic here: https://gunkies.org/wiki/KDJ11-B_CPU

I was hoping the answer to boot media would be as "simple" as making a bootable image and dd'ing to a Zip disk. I should be able to manage this along with building a console cable.

I'm sure you'll hear more as I move forward!


John Hudak<mailto:jjhudak at gmail.com>
October 11, 2022 at 12:35 PM
Thanks for the clarification Dave.  About the bulkhead, I was not referring to the on-board connectors on the KDJ11-B. When the OP mentioned 'bulkhead' I thought he meant the circuit board that contains DB9, DB25, etc. which is usually bolted to the chassis. The link I posted described the connections from the on-board SLU connector to the bulkhead connector.  DEC had a number of bulkhead configurations on their machines.  In any case, I re-read the OPs post and realized his system does not have the bulkhead connector, on the two 10-pin Berg/IDC connectors on board.
To clarify things, the link I posted:
https://gunkies.org/wiki/DEC_asynchronous_serial_line_pinout#10_pin_header
describes the pinouts for the 10-pin Berg connector.

John






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Dave McGuire<mailto:mcguire at neurotica.com>
October 11, 2022 at 8:27 AM
  Just expanding on a few points below.

On 10/11/22 00:48, John Hudak wrote:

A nice system - Congrats.B  This should keep you entertained for hours.
The bulkheads for console SLU differed according to what the machine was (Qbus, Unibus) and they varied within the backplane family.

  Steve said he has a KDJ11-B processor board.  This processor has two onboard SLUs which use the 10-pin connectors, not the 40-pins.


I think you will need to know the disk type emulation the cpu is expecting to boot from.B  This info is contained in the boot proms and configured via the onboard jumpers.

  There's virtually no chance of it being anything other than MSCP. Several companies made Qbus SCSI host adapters; all of them (or nearly so) implement MSCP.


Not sure how to get the images onto the zip drive.

  dd


To run BSD 2.x requires separate I&D space and the usual upgrade was to exchange the 11/23 cpu board for a 11/73 board.

  Not quite.  2.11BSD, the last release, is the first release to require split I/D space.  2.10BSD and prior will run on the 11/23.

            -Dave
John Hudak<mailto:jjhudak at gmail.com>
October 10, 2022 at 11:48 PM
A nice system - Congrats.  This should keep you entertained for hours.
The bulkheads for console SLU differed according to what the machine was (Qbus, Unibus) and they varied within the backplane family.
Without having my notes in front of me, the information on this wikipedia page is very helpful.  From what I can remember, this looks to be correct:
https://gunkies.org/wiki/DEC_asynchronous_serial_line_pinout
The pinouts on the various bulkheads show what pins on SLU connector/CPU board to connect to.

Back in the day, I designed and built my own SLU interface/bulkheads for our lab machines. If I can find my notes, I'll update the info.
If you haven't already, you should check out bitsavers for some very useful documentation on the KDJ11-B. Specifically the KDJ11-B CPU Module Users Guide EK-KDJ1B-UG-001
and
KDJ11-B CPU system Maintenance EK-247AA-MG-001

Useful information on how to configure the jumpers on the board, and set the baud rate for the SLU.  The joys of ODT are well explained in the second manual.  The User Guide does a good overview but the System Maint manual has more detail

You can configure the CPU board to use the onboard SLU as the console or another asynchronous serial card such as the DLV11-J. Not sure what config you have. The manual for the DLV11-J is also on bitsavers.

Software - I can't help much here as my machines use RL02 and I have actual packs for RT11 and RSX11.  OS's can be loaded using SIMH in at least a couple of ways.  There is a TU-58 emulator via a serial line interface.  As you mentioned, you need to get the SLU working to use it.  IIRC, there are RT and RSX-11M versions (documents and compressed images , RL01 format I think). I think you will need to know the disk type emulation the cpu is expecting to boot from.  This info is contained in the boot proms and configured via the onboard jumpers.
Not sure how to get the images onto the zip drive.
IIRC, the 11/23 could only run UNIX v5, V6.  To run BSD 2.x requires separate I&D space and the usual upgrade was to exchange the 11/23 cpu board for a 11/73 board.
Good luck
J











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Steve Hatle<mailto:steve.hatle at gmail.com>
October 10, 2022 at 6:00 PM
I recently came into an 11/23+ machine. It has a KDJ11-B CPU board, a MSV11-Q memory board, a SCSI board that was driving a SCSI Zip drive for boot media, and two cards that were used to control a laser cutter.

First issue is that there is no "bulkhead" to bring out the console connection, so I need to figure out how to get a terminal connected to the J1 SLU connector. This is 9 pins, but I can't seem to find definitive info on what the pin assignments are here, and exactly which pin is #1. Once I know these things, I'm sure I can make a cable with TX/RX/GND to get a console going. Anyone have pointers? I found a set of schematics but what I think is showing J1 doesn't make sense to me.

Then, I need to figure out how to get software set up to run the thing. I didn't receive any of the Zip media previously used, or any documentation for the machine. I'm guessing I can use SIMH and perhaps build a bootable Zip or other SCSI drive, but that will need to wait until I can at least talk to the thing. Lacking any other serial ports, I don't think I'll be able to take advantage fo the TU58 emulator or other solutions.

Looking forward to getting this guy up and running!

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