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WHOOO HOOO! I'm getting a PDP-11/23!

smp

smp

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Joined
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Location
Bedford, NH, USA
Hello all,

I looked at the CCTALK Digest yesterday afternoon, and I saw that there was a PDP-11/23 available for private sale. I sent off a message, got a response, made an offer, and voila! I am about to embark on a brand new adventure!

This is a PDP-11/23 in excellent shape, including:

- BA11-N chassis with H9273 4x9 Q18/CD backplane
- M8186 11/23 KDF11-A CPU
- Qty 2, M8044-DB MSV11 32 KW RAM
- M7940 DLV11 SLU
- M8012-YA BDV11 bootstrap, termination, ROM

And, to top it all off, this machine looks like it is in museum condition. No scratches, no dust, everything clean as if it just came from the factory.

I have been looking at so much junk on eBay in the few to several hundred dollar range, and nice looking machines in the few thousand dollar range from re-sellers. I feel so lucky to have this opportunity to start with a known good working machine to learn on and build up over time.

Please stand by. I know for sure that I will return with questions. Your assistance will be greatly appreciated in the future as I learn about this whole new area of vintage computing that I've never touched before.

smp
 
Nice :D Brimore's got some QBus memory cards in that collection of parts, so you might want to get those in order to fill 'er up a little more...
 
Very nice! Sounds like you have a mostly-complete system to play around in PDP-11 land. If you don't have a storage device, I'd recommend getting another DLV-11 or 4-port DLV-11J and doing TU-58 tape emulation with a PC. There are several emulator applications available for DOS/Linux that stream tape images over the PC serial port.
 
smp said:
Hello all,

I looked at the CCTALK Digest yesterday afternoon, and I saw that there was a PDP-11/23 available for private sale. I sent off a message, got a response, made an offer, and voila! I am about to embark on a brand new adventure!

This is a PDP-11/23 in excellent shape, including:

- BA11-N chassis with H9273 4x9 Q18/CD backplane
- M8186 11/23 KDF11-A CPU
- Qty 2, M8044-DB MSV11 32 KW RAM
- M7940 DLV11 SLU
- M8012-YA BDV11 bootstrap, termination, ROM

And, to top it all off, this machine looks like it is in museum condition. No scratches, no dust, everything clean as if it just came from the factory.

I have been looking at so much junk on eBay in the few to several hundred dollar range, and nice looking machines in the few thousand dollar range from re-sellers. I feel so lucky to have this opportunity to start with a known good working machine to learn on and build up over time.

Please stand by. I know for sure that I will return with questions. Your assistance will be greatly appreciated in the future as I learn about this whole new area of vintage computing that I've never touched before.

smp
Click to expand...

Congrats, did you get the RL01 and Rx02 as well?
 
glitch said:
If you don't have a storage device, I'd recommend getting another DLV-11 or 4-port DLV-11J and doing TU-58 tape emulation with a PC. There are several emulator applications available for DOS/Linux that stream tape images over the PC serial port.
Click to expand...

Hi Glitch,

Thanks. And, thanks for the tip, too. It looks like that may be one of the things that I will be looking to do, once I get up and running.

smp
 
DaveH said:
Congrats, did you get the RL01 and Rx02 as well?
Click to expand...

Hi Dave,

Thanks very much.

Yes, there was a 2-board quad-wide set of cards, M8013 & M8014, as well as another double-wide card, M8029, also included in the sale. These were listed as likely working but not tested. They will be giving me plenty of opportunities for furthering my knowledge about their operation, and for potentially building up my system from this great starting point. I have an old chassis that contains a couple of old 8 inch floppy drives, so there might be some experimenting with the M8029 in my future!

smp
 
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smp said:
Hi Glitch,

Thanks. And, thanks for the tip, too. It looks like that may be one of the things that I will be looking to do, once I get up and running.

smp
Click to expand...
Congrats. I know you will have many pleasurable hours.
 
Pretty bad ass :) Let us know how it goes and some pics if you get it. I think I know which one you're getting, did either of you comment on it being sold on cctalk? er.. I mean just out of curiosity lol not being etiquette police :)
 
barythrin said:
did either of you comment on it being sold on cctalk? er.. I mean just out of curiosity lol not being etiquette police :)
Click to expand...

Hi barythrin,

I am very new to CCTALK, and I'm only skimming the digests that come to me a few times per day right now.
Yes, I mentioned that this came about because I saw the posting on CCTALK yesterday afternoon in the OP.
Are you not supposed to post anything for sale on CCTALK?
If so, then I am even more lucky than I thought to have scored this machine!

smp
 
smp said:
Are you not supposed to post anything for sale on CCTALK?
Click to expand...

Oh it's totally allowed and everyone is usually happy to see things for sale :) I was just asking out of curiosity since I saw a few PDPs for sale recently and was just curious which one was sold :)

I realized after posting it might come across as me complaining or trying to correct you and that wasn't at all what I was trying to imply, I was just being nosy and curious if it was that one or not lol Thanks for posting the pics too.
 
You got yourself an old school RL-01 control card set (M8013/M8014) and a RX-02 controller (M8029) RX-02 Floppy controller. I had the same configuration in my 11/23 before I went to a newer memory card.
The bootstrap/terminator card (M8012) is great because it has the different loaders for RX, RL or most other DEC stuff and the little set of diagnostic lights on the back.
Do yourself a favor and download the manuals on everything and start studying. The KDF-11A User Guide will be the most useful and informative, and then you will want to know if you have the MMU and FPU options, don’t think I have ever seen one without the MMU but only rarely see the FPU installed.
 
Very nice!!! Congratulations :D I know how good it feels to get a new system to play with and learn on. This is a really nice one, too!
 
OK, folks, here I am, back again, for an update.

Last week, I received the system on July 3rd, and spent a fair amount of time unpacking and physically inspecting the system. All seemed to be well, with the processor board wiggled out of its slot, but everything else intact and undamaged. I have to say that the seller took tremendous pains to properly package the system for transportation. Very nicely done! Anyway, I was able to get the machine properly assembled without the extra boards that I do not have use for immediately, and I was able to power it up and watch the lights on the M8029 terminator/boot board. All appeared to be in order. Since my wife was interested in going out and getting something to eat, I decided that was enough for the day and kept myself out of any further trouble. ;-)

On July 4th, I first spent some time to hack together a cable to go from the M7490 serial I/O card to my laptop computer that I use as a terminal. Of course, I got it wrong and I had to use a null modem connector (after the initial panic attack), but I got to see that the system properly booted to the START? prompt, and when I answered N, it dropped into ODT and accepted commands from there. YAY!

I later spent the time to properly construct the cable so that it will actually last and not fall apart upon the slightest wiggle - I also fixed the transmit and receive data wires so I no longer need the null modem, too.

Then I spent a couple of hours banging in small test programs that I was able to find on the Internet, and all seems right in my new world of DEC equipment.

I was off on travel to visit with family over the rest of the long holiday weekend, and beginning of this week.

So, now I would obviously like to proceed with interfacing with something that will actually allow the system to boot up with more than ODT. As I mentioned before, I think my best first bet will be to interface with a TU-58 tape emulator. Hmmm, since I have only one SIO port on the M7490, I saw that Glitch was correct in that I will have to acquire an additional SIO port of some kind in order to interface to both a console and the TU-58 emulator at the same time.

I am happy to report that I have now successfully acquired a DLV11-J four line asynchronous serial I/O card, which is scheduled to arrive sometime like the middle of next week. Hopefully, I can first install it in place of the M7490, and get back to the same place that I am now, and then proceed to interface to the TU-58 emulator.

Lots of fun! I am having a blast with this stuff, learning about an entirely new set of equipment for me. I'll be back again later with more updates as my adventure progresses.

Thanks for listening.

smp
 
May want to consider a RL-01 drive or two, you already have the controller for the 01. Brimore with the Dec stuff for sale has two but there on the wrong side of the country, but they do have the slide rails, cables and terminators and those are the hard parts to get. Other than that you can get a RX-02 but that will cost more and stores less, I tend to lean towards the old RL drives because they are indestructible and cheap and my RX drive have been giving me nothing but pain. One of the projects around here is to work up the TU-58 emulator just have not gotten to it yet but do not see that as an easy way of loading things like operating systems or complex programs.
 
You might want to look at vtserver - it has the ability to copy stuff to/from disks via the console port, so you can proceed without the second serial port. The only downside is that IIRC it requires 190K+ of memory...
 
Roe said:
You might want to look at vtserver - it has the ability to copy stuff to/from disks via the console port, so you can proceed without the second serial port. The only downside is that IIRC it requires 190K+ of memory...
Click to expand...

OK! I need some help with vtserver.

While I am waiting for my DLV11-J to arrive, I thought that I would play around a bit with this...

I have studied Mr Engdahl's web site (http://home.windstream.net/engdahl/vtserver.htm) and I see that vtserver works in place of my terminal program - and he has a version that works on a PC rather than a Unix box.

So, the first thing I see is that the slowest serial rate the MS DOS version can go is 4800 bps, and, of course, my M7490 is strapped for 2400 bps. Sigh. Well, it wasn't a real big deal to re-strap the board for 9600 bps, I just hate de-soldering and re-soldering stuff on these old boards, especially when it looks like this particular board has been re-strapped a few times in the past. So far, so good. My M7490 is now communicating at 9600 bps.

So, I start up with my Hyper-terminal window, get the START? prompt, answer N, and drop into ODT with the @ prompt. Next, I close my Hyper-terminal session, and open a DOS window, navigate to my vtserver folder, and invoke vtserver per the instructions: vtserver 9600

Bingo, the vtserver program starts up, and announces that it is "running command echo," indicates "ECHO is on," gives a list of tape records (none of which I actually have), indicates it is "opening port /dev/ttyp9 ... rate=9600 Port open," and then proceeds to print out line after line of @.

OK, so I try not to panic too much, even though I have little idea of what I am doing with DEC equipment and less idea about this vtserver. I found that vtserver seems to be continually typing out whatever the last character it received from ODT. Of course, the @ prompt makes sense. If I type 1000, I get a small bunch of 1s echoed back until I type the first 0, then I keep getting 0s until I type /. Then, I see the normal response from ODT, which is 000000. Then the screen starts scrolling up at the same rate, but with blanks being printed, as that was the last character that came from ODT after it sent the contents of memory location 001000, as I requested. If I hit return, I go back to constant @, because ODT goes back to the @ prompt.

So, I believe that my computer is behaving just like it should, but vtserver certainly should not be acting this way, I don't think.

I remember that vtserver is supposed to have an init file - a file called .vtrc, but I can only find instructions for using this file on a Unix machine, not on a PC. The first line of the file is supposed to set up the serial port with a command like "stty -f /dev/ttyid1 9600 cs8 clocal -crtscts." The second line is supposed to call out the actual serial port with a command like "/dev/ttyd1." Then the third line is supposed to invoke the copy command, to send a file over to the PDP-11, and finally, the fourth line is supposed to be a file name of the file to be sent to the PDP-11.

The Unix way of specifying serial I/O ports is obviously not the same as COM 1 on the PC. Should I try to make a .vtrc file and use the hint I got from the vtserver sign-on message? It looks like I could do the following:

stty -f /dev/ttyp9 9600 cs8 clocal -crtscts
/dev/ttyp9

Will doing this foul up my already working COM 1 port connection? Will a .vtrc file even be consulted in this DOS window version of vtserver?

And, of course, I do not yet have a file to be copied over to the PDP-11, so invoking the copy command is fruitless at the moment. I see all the messages posted everywhere that RT-11, et al, are all still copyrighted, but DEC is out of business and Mentech took over, but Mentech is now out of business... So, soon, I will be wondering just how to get a copy of RT-11 for myself...

If anyone has a suggestion, I would be happy to hear it. I don't know why this one (and only) version of vtserver that works in a DOS window on a PC should be constantly echoing the last character it receives from ODT.

Thanks for listening!
smp
 
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smp said:
I am happy to report that I have now successfully acquired a DLV11-J four line asynchronous serial I/O card, which is scheduled to arrive sometime like the middle of next week. Hopefully, I can first install it in place of the M7490, and get back to the same place that I am now, and then proceed to interface to the TU-58 emulator.
Click to expand...

Fantastic!! Yeah, that will be a good place to start.

The DLV11-J can be a pain to configure because of the wire-wrap jumpers used - do you have a wire wrap tool you can use on it? If not you can probably jury rig the jumpers out of whatever you have lying around. It sounds like you're plenty resourceful!

If you need guidance, the DLV11-J configuration guide can be found here: http://decdoc.itsx.net/uq/unfinished/DLV11-J Configuration Guide (M8043).tif

And the schematics with additional jumper information can be found here: http://bitsavers.trailing-edge.com/pdf/dec/qbus/MP00586_DLV11-J_Feb78.pdf

There seem to be several variations of the card, if I remember correctly, so it may not _exactly_ match either of those. If you need guidance just shout and I'll try to remember what I know about them (hint: probably not much :^)

-Twylo
 
smp said:
OK! I need some help with vtserver.

While I am waiting for my DLV11-J to arrive, I thought that I would play around a bit with this...

I have studied Mr Engdahl's web site (http://home.windstream.net/engdahl/vtserver.htm) and I see that vtserver works in place of my terminal program - and he has a version that works on a PC rather than a Unix box.
Click to expand...

OK, I have made a bit of progress with my experiments.

First, I found that there was a .vtrc file, and that was the source of the list of files that I did not understand. The .vtrc file has the command ECHO as the first line - this instead of the Unix command line must take care of utilizing the already existing SIO connection on COM 1. The second line is indeed /dev/ttyp9, as I guessed it might be. Then, there is the option to invoke the copy command and have a file name of the file to be copied, or the mysterious list that I saw before. I have experimented with both... oh, yeah, I found a bunch of those files in the package provided by the original author at: ftp://minnie.tuhs.org/pub/PDP-11/Vtserver/. I gathered them all into my vtserver folder.

I also found a README2 file where Mr. Engdahl indicates that the invocation should be "vtserver 9600" (for me with my 9600 bps port open), and he also indicates that ^B sends a break, and ^A sends the boot code at the next opportunity. I found that invoking vtserver without any lines 3 through whatever in the .vtrc file gets me to the place where I am getting continuous @, like before, but sending a ^B pauses that for a little bit, and sending ^A sends a bunch of code over to the PDP-11 via ODT commands, and then seems to jump to execute that code, because the PDP-11 (I think) then says "No such tape record 0."

So, I guess I really need a program file to send over to the PDP-11...

Does anyone know where I can obtain a file of RT-11 in the correct form to be sent to the PDP-11 by vtserver?

Thanks for listening!
smp
 
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VTserver is designed to download disk images to be stored on local disk storage attached to your PDP-11.

Since (it appears) you are running your system barefoot (ie, no local storage at all), not sure what benefit VTserver will provide for you.

If you want to run some software (like diagnostics) then the TU-58 emulator would be a better choice to start with.
 
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