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What did I do to my PDP-8 today.

thunter0512 said:
I got tired looking at the beaten up bezel of my PDP-8/e:

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I went to the local hardware store to get some paint which looked to be similar enough to the DEC white:

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After spending a few hours cleaning off the old paint using paint stripper, steel wool and elbow grease I spray painted the bezel and let it dry for 72 hours:

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Here is how it looks after I re-installed the bezel:

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The colour is close enough for me and it is more pleasing to look at (click on the thumb nails above to see the photos in full size).

Eventually I will deal with the case lid which cries out for a paint job too.

Tom
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I got exactly the same paint from Bunnings two weeks ago;)
 
Pretty close to uploading Console Serial Disk Version 1.0 to github. I played several games of chess on my 8/e using CSD as the boot since there are currently no other peripherals on the machine.

And I didn't play the computer, it is not a very good opponent. Instead I played it against three of the chess.com bots in order to try to figure out its rating. My own rating when I played in tournaments was a little over 1500 USCF in the 1980's. In all three games the PDP-8 played as black. The first game was against a bot called Aron with a rating of around 700. The 8 had no problems and mated Aron in 21 moves. The second game was against a bot called Nelson with a rating of 1300. Again the 8 was able to win but it took 35 moves to do so. The final game was played against a bot called Antonio with a rating of 1500. This time the game ended in a draw by repetition at move 28. The PDP-8 chess program Chekmo II does not know about the repetition rule and while it had a 2 pawn advantage it does not understand two rook endgames. It should have been a win. Need more games to get a feel for rating. It would be best to play it against people but chess.com frowns on this as a violation of fair play. However, it does not play well enough to get flagged as a cheater. It got an accuracy rating of only 44% in the second game.
 
Qbertnix said:
Lichess allows computers to play human players if you create a bot account
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I was not aware of that. I am not sure it applies as there is little chance I am going to write a program to interface between one of my 8 cpu's and the Lichess world. I think there is less chance I would want to leave an 8 running all the time. I suppose you could run something like simh on a 486 to get close to the correct speed. It is really only interesting from the historical aspect of an early chess program. Thanks for the pointer, I will look into it further.

I managed to be the intermediary three times between the 8 and the bots but only because I found it interesting to try to predict what move Chekmo II would come up with. I don't understand at all the reasoning behind the people who use one of the powerful chess engines to cheat. It seems like a lot of work for a dubious at best reward.
 
A few years ago, I was quite keen to interface CHEKMO-II to Stockfish to test its abilities, but that was more work than I cared to do at the time. It would be a fun project, though.
 
Today I grabbed a copy of CJL's WHATAMI.PA. I converted it from DOS format and then futzed with the formatting so no line is longer than 71 characters. 71 characters is the limit for the TTY: device. When the 72nd character is received a CR/LF is echoed which messes up my text sending function in console serial disk. I also removed a comment section talking about Kermit as it has nothing to do with this program.

I am going to include this on the csd1.img. It identifies the CPU it is running on. FOCAL does this as well but this is easier to understand. I started writing one of these years ago.

I am thinking of doing a command line option to csd such that instead of booting OS/8 it will run some self tests first. The first part of that would be to identify the processor so that the correct tests could be applied. I am not going to do this now but it seemed like a fun way to get some more time using CSD.
 
DougIngraham said:
Today I grabbed a copy of CJL's WHATAMI.PA. I converted it from DOS format and then futzed with the formatting so no line is longer than 71 characters. 71 characters is the limit for the TTY: device. When the 72nd character is received a CR/LF is echoed which messes up my text sending function in console serial disk. I also removed a comment section talking about Kermit as it has nothing to do with this program.

I am going to include this on the csd1.img. It identifies the CPU it is running on. FOCAL does this as well but this is easier to understand. I started writing one of these years ago.

I am thinking of doing a command line option to csd such that instead of booting OS/8 it will run some self tests first. The first part of that would be to identify the processor so that the correct tests could be applied. I am not going to do this now but it seemed like a fun way to get some more time using CSD.
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Where would I find a copy of CJL's WHATAMI.PA?
Google search didn't find it for me.
 
thunter0512 said:
Where would I find a copy of CJL's WHATAMI.PA?
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I've never been that happy with WHATAMI.PA. It works, but as an expository tool about how to tell which model you are running on, and how to avoid the quirks of various models, it isn't that great. As part of the SIMH enhancement I've been working on, I have wanted to create a new "diagnostic" which would enumerate the model-specific quirks of your machine, identifying the model in the process.

Of course, there are always more projects like this than time to do them.
 
thunter0512 said:
Where would I find a copy of CJL's WHATAMI.PA?
Click to expand...
I dislike that greenbar PDF! Here is a link to the parent directory that has both .PAL and .PDF.

http://www.ibiblio.org/pub/academic/computer-science/history/pdp-8/Generic Programs/

I haven't looked at the HELLOWORLD program yet.

vrs42 said:
I've never been that happy with WHATAMI.PA. It works, but as an expository tool about how to tell which model you are running on, and how to avoid the quirks of various models, it isn't that great. As part of the SIMH enhancement I've been working on, I have wanted to create a new "diagnostic" which would enumerate the model-specific quirks of your machine, identifying the model in the process.
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I wrote a program many years ago to generate all Group 1 OPR instruction output. The only machine I had at the time was my Straight 8. I wanted to run it on all CPU's so I would have a way to know exactly what each machine did with the patterns it did not support. That way you can make an emulation that exactly matches the real thing. At this point I would have to dig to find that program and the output (many hours capturing at 9600 baud).
 
Here's my PDP-8/E booting from an RX02 drive and formatting disks in the other drive.

On top of the RX02 (in the Tardis) is a Raspberry Pi 3B+ running Serial Disk.

On the right of the laptop is a Dual SA-800 Drive Greaseweazle system for formatting and copying 8" diskettes.

I was able to rejuvenate some unformattable disks by erasing and then writing a zero directrory OS/8 (981 block) image on top.

I copied the RX02 boot image from my RX02 emulator to a floppy using the Greaseweazle.
 

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Vince and I are shortly being joined by Doug to play with Vince's 8/E and 12, and maybe even an 8/I. Earlier in the week, we spent much of the time debugging a VC8E clone that Vince designed. The basics of it aren't that complex, but to support different displays, some of which have color and storage support, there are lots of polarity, voltage, and timing considerations that must be made. We've been trying to find ways of better testing the timing portions, and have found that the DONE flag does not always get set after an operation. Unfortunately, neither the oscilloscope nor logic analyzer seem to have the depth we need to see the entire issue, as it seems nondeterministic and thus triggering the test equipment is challenging.

PXL_20230820_052432652.jpg

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I would share my DSLR photos, but the forum won't let me upload them due to their size... So, in the meantime, you'll have to enjoy the not so great photos of the Tek 464 rather than the nice photos of the Tek 611. The 611 is a mighty fine display!

We put the VC8E aside to work on Vince's very elegant 5 paddle card MM8I solution. It turns out that it requires very few components to fill in the rest of the 32k memory space on an 8/I or 12—not dissimilar from the Omnibus memory board design. We've been experimenting with the 12, but the 8/I shares the same external memory bus architecture. We still found bugs, but these will be fixed in another respin of the board set.

PXL_20230823_082414963.jpg

For those planning on showing up to VCF MW, Vince is planning to bring some show and tell, but due to lack of overhead space on the plane, the PDP-12 will have to remain at home until next year.

In the meantime, stay tuned for more adventures from the trio.
 
antiquekid3 said:
Vince and I are shortly being joined by Doug to play with Vince's 8/E and 12, and maybe even an 8/I. Earlier in the week, we spent much of the time debugging a VC8E clone that Vince designed. The basics of it aren't that complex, but to support different displays, some of which have color and storage support, there are lots of polarity, voltage, and timing considerations that must be made. We've been trying to find ways of better testing the timing portions, and have found that the DONE flag does not always get set after an operation. Unfortunately, neither the oscilloscope nor logic analyzer seem to have the depth we need to see the entire issue, as it seems nondeterministic and thus triggering the test equipment is challenging.

View attachment 1262938

View attachment 1262940

I would share my DSLR photos, but the forum won't let me upload them due to their size... So, in the meantime, you'll have to enjoy the not so great photos of the Tek 464 rather than the nice photos of the Tek 611. The 611 is a mighty fine display!

We put the VC8E aside to work on Vince's very elegant 5 paddle card MM8I solution. It turns out that it requires very few components to fill in the rest of the 32k memory space on an 8/I or 12—not dissimilar from the Omnibus memory board design. We've been experimenting with the 12, but the 8/I shares the same external memory bus architecture. We still found bugs, but these will be fixed in another respin of the board set.

View attachment 1262939

For those planning on showing up to VCF MW, Vince is planning to bring some show and tell, but due to lack of overhead space on the plane, the PDP-12 will have to remain at home until next year.

In the meantime, stay tuned for more adventures from the trio.
Click to expand...

That's pretty exciting news! Looking forward to the next chapter in Michigan.
 
The VC8E clone looks promising. Is this Roland's version or is this something Vince did independently?
I am intrigued by the text plot "THE BIG DOG ATE BEANS FOR BREAKFAST". What software was used to plot the text?
 
I think I can write a program to trigger an event on an output pin, or even the serial line, when DONE is not asserted in the expected amount of time. Maybe that will get us somewhere.

The text plot is from the VC8TST program, which is just exercising drawing text on the screen and not much else. I am sure it's up on Vince's site somewhere in the depths of the repository.

The VC8E clone is Vince's design using our favorite ATF1508 CPLD as the main brains, but the current Verilog description is taken directly (though tweaked slightly) from the schematic translation tool Vince wrote in Perl.
 
I use a pico USB scope with both analog and digital inputs. It can be set to trigger on a single event or a complicated pattern.
 
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