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

Steve Hatle steve.hatle at gmail.com
Tue Oct 11 14:46:10 EDT 2022


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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