• Please review our updated Terms and Rules here

Changing a plain PDP-11/23 into a PDP-11/23+

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
Hello all,

As you may recall, I have a small PDP-11/23 system, made up of the following:

BA11-N Chassis
H9273 Backplane
M8186 Processor
M8044-DB 32K Word Memory (qty=2)
M7940 Serial I/O (qty=2)
Emulex UC07 SCSI Interface
open row
open row
M8012 Diagnostic / Boot

I have cobbled together an old Macintosh SCSI hard disk drive and a SCSI Zip Drive for disk storage, and I can boot and run RT-11 (I have to manually type in the bootstrap code via ODT for booting up from a cold start).

I see this auction on eBay for a M8189 PDP-11/23+ Processor board with cab kit:

http://www.ebay.com/itm/291440874272?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Since I really do not know what I am doing, can anyone offer me some advice on if I might be able to use this M8189 processor in my chassis and backplane? Would this processor board replace all of my boards, except the Emulex UC07 SCSI Interface? Would I keep my current memory boards? Would this processor still need the M8012 Diagnostic / Boot board?

Finally, is this a reasonable price to pay for this processor and cab kit? Hopefully it is, and I might be able to go on a new DEC adventure.

Thanks in advance,
smp
 

gslick

Veteran Member
Joined
Dec 30, 2010
Messages
2,112
Location
Seattle, WA
Instead of buying this M8189 + cab kit for $295:
http://www.ebay.com/itm/291440874272

You could buy this M8189 for $150 and make your own console cable:
http://www.ebay.com/itm/131538133160

Or add this cab kit for $65 (or maybe lower offer accepted) and still come out cheaper:
http://www.ebay.com/itm/161641182794

The first M8189 includes the KEF11-AA microcode option, the second one doesn't. You could buy one of these for $15 (or maybe lower offer accepted) to add it if you wanted:
http://www.ebay.com/itm/390174518063


One issue though is that you have an H9273 Backplane, which is only Q18/CD instead of the H9276 which is Q22/CD, so you would be limited to 256KB.

With a M8189 PDP-11/23+ CPU you wouldn't need the two M7940 DLV11 or the M8012 BDV11. You would still need memory as the M8189 has no onboard RAM.

Also, since you have a Q/CD backplane you should be able to use an M8190 KDJ11-B 11/73. The last couple of those I bought on eBay were around $75 each. Too bad I don't see any deals like that up there now.
 
Last edited:

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
Hi Glen,

Thanks very much for your reply. Obviously, I had not looked around on eBay enough, and hadn't found the other options you mention.

Another question I have about possible processor swaps is, can I swap my M8186 processor for an M8192, like these:

http://www.ebay.com/itm/M8192-YB-PD...165?pt=LH_DefaultDomain_0&hash=item25773b22b5
http://www.ebay.com/itm/DEC-M8192-P...729?pt=LH_DefaultDomain_0&hash=item2ed3322221

These are also less expensive, and maybe would be a simple swap, one-for-the-other?

What might be the performance differences among these processors? Is it easy to say? Is it easily seen?

Thanks, again, in advance.

smp
 

gslick

Veteran Member
Joined
Dec 30, 2010
Messages
2,112
Location
Seattle, WA
If you already have a working M8186 11/23 CPU system there isn't much you would gain in spending more than $100 switching to an M8189 11/23+ CPU system, especially if you have updated the M8012 BDV11 to the 11/23+ KDF11-BH firmware.

If you were to upgrade to an M8192 KDJ11-A or M8190 KDJ11-B the main advantage other than speed is the addition of the split I/D capability which is necessary to run 2.11BSD. The M8190 KDJ11-B has onboard firmware and an M8012 BDV11 would not be necessary. The M8192 KDJ11-A does not have onboard firmware but I don't think you can install appropriate firmware on an M8012 BDV11 from reading uNOTE #003 and uNOTE #004:

http://www.bitsavers.org/pdf/dec/qbus/oemMicronotes.pdf

You should still be able to use the Emulex UC07 onboard firmware to boot from that controller.
 

TiggerLAS

Experienced Member
Joined
May 20, 2008
Messages
99
Location
Tacoma, WA
The H9273 is readily upgraded to 22-bit, by bussing the appropriate signal lines on the backplane.
I'm pretty sure that I posted the instructions, and some pictures in another thread some time ago.

I'm all about reducing board count in systems, so any of the Quad 11's would be an upgrade in my opinion.
They will give you one or two SLU's, memory management, optional floating point, and bootstrap/diagnostics.
The 8190 will get you the most bang for the buck, since they're fairly common.

If you can live without floating point, then pick up a QED93.
It's got CPU, bootstrap, line time clock, 8 serial lines, and 4MB of memory on-board.
You would literally end up with two boards in your chassis. The QED93, and your disk controller.

Note that there are a number of operating systems that won't work with the QED because of the lack of floating point.
This includes later versions of RSTS/E, and from what I've heard, a number of various Unix implementations.
 

pbirkel@gmail.com

Veteran Member
Joined
Apr 7, 2013
Messages
561
Location
Silver Spring, MD, USA
Note that there are a number of operating systems that won't work with the QED because of the lack of floating point.
This includes later versions of RSTS/E, and from what I've heard, a number of various Unix implementations.

What would be the most recent version(s) of the various applicable OS that are known to work with the QED93? it does otherwise look like a nice board.
 

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
Thanks very much for all your replies.

You folks have given me quite a bit to think about. If there isn't very much actual performance difference, then maybe I'm better off saving my money for something else. I certainly get the point about reducing the number of cards in my system. I have tried in the past to get an M8043 four port serial I/O card to work in my system, instead of the two M7490 boards I have now, but I have not been successful. It may be that my M8186 processor has too early a version of printed wiring, if I'm reading the Micro-Notes correctly. Anyway, that was the attraction for me to the M8189 board - processor, two serial I/O ports, and boot PROMS all on one board. Plus, for me, the cab kit gets me away from my hay-wiring SIO cables.

Thanks again. If you have any more thoughts, please keep them coming.

smp
 

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
If you can live without floating point, then pick up a QED93.
It's got CPU, bootstrap, line time clock, 8 serial lines, and 4MB of memory on-board.
You would literally end up with two boards in your chassis. The QED93, and your disk controller.

Note that there are a number of operating systems that won't work with the QED because of the lack of floating point.
This includes later versions of RSTS/E, and from what I've heard, a number of various Unix implementations.

Hi, TiggerLAS,

By QED93, do you mean this:

http://www.ebay.com/itm/QED-993-Single-Board-Q-Bus-CPU-w-cab-kit-/200600166676?rmvSB=true

Or this:

http://www.ebay.com/itm/QED-993-Sin...479?pt=LH_DefaultDomain_0&hash=item2eb9f5544f

These are from the same seller, but one says it includes the cab kit, and then in the description it says the cables shown are not included. Do you know what the cable is? By any chance, is it a simple cable to construct? Do you have a pointer to a user manual?

Thanks in advance,
smp
 

gslick

Veteran Member
Joined
Dec 30, 2010
Messages
2,112
Location
Seattle, WA
Hi, TiggerLAS,

By QED93, do you mean this:

http://www.ebay.com/itm/QED-993-Single-Board-Q-Bus-CPU-w-cab-kit-/200600166676?rmvSB=true

Or this:

http://www.ebay.com/itm/QED-993-Sin...479?pt=LH_DefaultDomain_0&hash=item2eb9f5544f

These are from the same seller, but one says it includes the cab kit, and then in the description it says the cables shown are not included. Do you know what the cable is? By any chance, is it a simple cable to construct? Do you have a pointer to a user manual?

Thanks in advance,
smp

The cab kit for the QED993 is actually a DEC 70-27975-01 cab kit that is used for the M8981 KDJ11-E PDP-11/93 CPU module.

There are two connectors, a 40-pin connector and a 60-pin connector. The signals for the console port are on the 40-pin connector. I just used a standard 40-pin IDE cable and left the 60-pin connector unconnected when I was trying out a QED993. I never got around to buying connectors and cable to build the 60-pin cable. It probably shouldn't cost too much for the parts.

Interesting that the seller has the QED993 with cab kit listed for $50 more than just the QED993 module, but also lists just the cab kit alone for $45. The actual sales history for that item shows them being sold around $25:

http://www.ebay.com/itm/200598035527
 

gslick

Veteran Member
Joined
Dec 30, 2010
Messages
2,112
Location
Seattle, WA
Thanks again. If you have any more thoughts, please keep them coming.
smp

Another option would be to pick up an M7554 KDJ11-D PDP-11/53. It's hard to find those in the regular chassis mounting configuration. The DECServer 500/550 version is a lot more common with the mounting bracket for BA213 style chassis. They have 2 onboard serial ports and either 512KB or 1.5MB of onboard RAM and make a simple system to setup with just the addition of a mass storage controller.

The downside of the M7554 compared to either the M8192 KDJ11-A or M8190 KDJ11-B is that the M7554 does not have cache memory so it will be slightly slower, and while floating point instructions are supported the FPA (Floating-point Accelerator) option is not available.

I only see the 512KB DECserver 500 versions listed on eBay at the moment in the $175-$225 (or best offer) range:
http://www.ebay.com/itm/111708401901
http://www.ebay.com/itm/251561484682
http://www.ebay.com/itm/151226916371
http://www.ebay.com/itm/200601994252

To use one of those as a standard PDP-11/53 you would need to replace the DECserver firmware EPROMs with the standard PDP-11/53 firmware. I have done that on a 1.5MB KDJ11-SD version which I use in BA213 chassis. In theory you could drill out the rivets that hold the S-handle mounting hardware to use it in a BA11 or BA23 chassis. I haven't tried that myself. If you do that removing the board from the backplane without ejector handles might be more difficult.

If you did pick up an M7554 and wanted a BA23 style cab kit for it www.jtcomputer.com (seller conflansrd on eBay) has the CK-KDJ11-D listed for $55. I bought one of those there.

-Glen

P.S. I would rather have a PDP-11/53 that can run everything than a faster QED993 on which I haven't been able to get RSTS/E 10.1 or 2.11BSD running.
 
Last edited:

TiggerLAS

Experienced Member
Joined
May 20, 2008
Messages
99
Location
Tacoma, WA
The M8189 isn't the best upgrade path from the M8186. . . unless you're just trying to reduce board count.

The 11/53 mentioned earlier would be faster, and has the advantage of having SOME memory on-board.

The M8190 (as long as it has the OPTIONAL floating point chip) will be the biggest,
affordable performance boost, that will be compatible with all of the available operating systems.
However, it has no memory on-board.
 

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
P.S. I would rather have a PDP-11/53 that can run everything than a faster QED993 on which I haven't been able to get RSTS/E 10.1 or 2.11BSD running.

Excellent! Thanks very much. This is exactly the kind of advice I was hoping I might get.

smp
 

TiggerLAS

Experienced Member
Joined
May 20, 2008
Messages
99
Location
Tacoma, WA
Only $1,735 ?

Methinks they need to lose one of those digits. . . and I'm not talking about the "1". ;-)

Check with Keyways.com. See what their hobbyist / un-tested M1890's go for these days.
Make sure it has floating point. I'd price it with, and without the cab-kit.
 

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
Check with Keyways.com. See what their hobbyist / un-tested M1890's go for these days.
Make sure it has floating point. I'd price it with, and without the cab-kit.

OK. Keyways web site shows M8190, M8190-AB and M8190-AE in stock. I have not yet asked for any quotation.

From my DEC Field Guide:

Code:
M8190       KDJ11-B     U   11/84 CPU: J11 CPU 15MHz with unusable socket for 
M8190                       FPJ11 and 2 SLUs, boot & diagnostic ROMs, 3 ROM 
M8190                       sockets, 8-Kbyte cache.
M8190		Refs: EK-KDJ1B-UG, uNOTE N#039

M8190-AB    KDJ11-BB    Q   J11 CPU 15MHz with 2 boot & diagnostic ROMs
M8190-AB                    FPJ11 compatibility (warm floating point, but
M8190-AB                    will accept FPA)
M8190-AB	Refs: EK-KDJ1B-UG, uNOTE N#039

M8190-AE    KDJ11-BF   Q/U 11/83-84 CPU J11 CPU 18MHz with 2 boot &
M8190-AE                    diagnostic ROMs, FPJ11-AA.
M8190-AE	Refs: EK-KDJ1B-UG, uNOTE N#025, N#030, N#035, N#039

I see the plain M8190 is a Unibus board, so that is not for me.

The M8190-AB is 15 MHz. I do not understand what "warm floating point" is. I get it that it has a socket (or sockets) to plug in an FPA.

The M8190-AE is 18 MHz. It is also tagged as Q/U, so that is scaring me, because I only have my Qbus backplane. No note about floating point at all.

It appears to me that I may want the M8190-AB. I probably want to go and look up Micronote N#039 next. Can you explain the differences between the M8190-AB and M8190-AE in simple terms?

Thanks a million for your continued attention.

smp
 

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
Hi Crawford,

Thanks very much for weighing in.

Yes, Glenn already pointed out a few eBay auctions (or BINs) for DecServer 500.

I am smack in the middle of confusing the heck out of myself with these possibilities for a different processor board. It all started out because I came across an auction for the M8189, which had two serial I/O ports and the boot ROMs onboard. Then, as usual for me, things evolved from there. I am now wading through many possibilities, with fairly little real understanding of what I am seeing.

Thank goodness that I actually have a good working system to start with. I will probably get overwhelmed with what I might be able to do, and whether or not that brings me any real performance improvement for my hacking around with my system. Right now, I am trying to remember if any or all of these options will still work in my Q18/CD backplane, for example.

The wild world of DEC PDP-11 systems is incredibly complicated.

I'm having fun trying to grasp all of this, though, so please continue to offer your thoughts and make suggestions.

smp
 

gslick

Veteran Member
Joined
Dec 30, 2010
Messages
2,112
Location
Seattle, WA
www.jtcomputer.com used to have a bunch of M8190 KDJ11-B boards. I bought my last two M8190-AE (18MHz with FPJ11) from them when they had several listed on eBay. They must have sold them all now. Maybe I should have bought more for a rainy day.

This is what they have listed on their website now. I paid less than half that as a best offer on eBay.
M8190-AB
PDP11/73 KDJ11-BB Q-BUS QUAD 15MHZ CPU MODULE WITHOUT FPJ11 CHIP (USABLE FPJ11 SOCKET, ACCEPT & RUN WITH FP CHIP)
$225.00

I also bought a few M8637 MSV11-JE 2MB PMI memory boards from them in the past when they had some listed on eBay. That's what you would want to use with a M8190 KDJ11-B in a Q22/CD backplane.

They still have some listed on their website. I paid less than that as a best offer on eBay.
M8637-E
MSV11-JE 2MB MEMORY
$75.00
 
Last edited:

smp

Veteran Member
Joined
Oct 4, 2011
Messages
1,701
Location
Bedford, NH, USA
www.jtcomputer.com used to have a bunch of M8190 KDJ11-B boards.

This is what they have listed on their website now. I paid less than half that as a best offer on eBay.
M8190-AB
PDP11/73 KDJ11-BB Q-BUS QUAD 15MHZ CPU MODULE WITHOUT FPJ11 CHIP (USABLE FPJ11 SOCKET, ACCEPT & RUN WITH FP CHIP)
$225.00

Hi Glen,

Thanks very much for this information.

I verified that I can find the same listing as you showed. I have also sent off a request for quotation to sales@keyways.com. We'll see what they come back with.

Just to verify (due to my anal and paranoid nature) the DEC M8190-AB will work in my Q18/CD backplane, right? Also, the DEC M8190-AB processor board will replace my M8186 processor, one of my M7490 Serial I/O boards, and my M8012 Diagnostic / Boot board, right? I will still need both of my M8044 32K Word memory boards (or another memory board that will go into a Q18/CD backplane), one of my M7490 Serial I/O boards for the TU-58 tape emulator, and also my Emulex SCSI Interface board, right?

Thanks a million for your continued attention.

smp
 
Top