PDP11

Discussion of anything and everything relating to chess playing software and machines.

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flok
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PDP11

Post by flok »

Only marginally on-topic, yet:

Image

This is an ESP32 microcontroller running my PDP11/70 emulator running UNIX 7 running the included chess program :-)

I have a question about the chess-program: does anyone know if the chess program from UNIX 7 ever participated in a tournament? And is its strength known?
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towforce
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Re: PDP11

Post by towforce »

Interesting!

The PDP-11 was a 16-bit computer launched in 1970, and some people say it was the best-selling minicomputer ever.

Having a quick look at its simulators, a lot of them seem to be on microcontrollers rather than on Windows (the top result for "PDP-11 emulator" is a JavaScript program to be fair). I wonder why? My guess: microcontrollers are the preferred platform for the kind of people that love the PDP-11 enough to run emulators of this computer.
The simple reveals itself after the complex has been exhausted.
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flok
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Re: PDP11

Post by flok »

towforce wrote: Thu Jun 20, 2024 10:24 am Interesting!

The PDP-11 was a 16-bit computer launched in 1970, and some people say it was the best-selling minicomputer ever.

Having a quick look at its simulators, a lot of them seem to be on microcontrollers rather than on Windows (the top result for "PDP-11 emulator" is a JavaScript program to be fair). I wonder why? My guess: microcontrollers are the preferred platform for the kind of people that love the PDP-11 enough to run emulators of this computer.
Well to me it felt like a real challenge, something that would be difficult to do. Because of the resource constraints. Eventually the difficulty was that I was not familiar with the PDP11 platform and not the embedded device (ESP32 SDK is very easy to work with).
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towforce
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Re: PDP11

Post by towforce »

flok wrote: Thu Jun 20, 2024 2:05 pm
towforce wrote: Thu Jun 20, 2024 10:24 am Interesting!

The PDP-11 was a 16-bit computer launched in 1970, and some people say it was the best-selling minicomputer ever.

Having a quick look at its simulators, a lot of them seem to be on microcontrollers rather than on Windows (the top result for "PDP-11 emulator" is a JavaScript program to be fair). I wonder why? My guess: microcontrollers are the preferred platform for the kind of people that love the PDP-11 enough to run emulators of this computer.
Well to me it felt like a real challenge, something that would be difficult to do. Because of the resource constraints. Eventually the difficulty was that I was not familiar with the PDP11 platform and not the embedded device (ESP32 SDK is very easy to work with).

Ironic! :)

One of the most famous Chess programs of the 1970s, Belle, was written on a PDP-11 by the famous Ken Thompson.

Here are some more PDP-11 programs - is yours on the list?
https://www.chessprogramming.org/Category:PDP-11
The simple reveals itself after the complex has been exhausted.
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flok
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Re: PDP11

Post by flok »

towforce wrote: Thu Jun 20, 2024 3:22 pm
flok wrote: Thu Jun 20, 2024 2:05 pm
towforce wrote: Thu Jun 20, 2024 10:24 am Interesting!

The PDP-11 was a 16-bit computer launched in 1970, and some people say it was the best-selling minicomputer ever.

Having a quick look at its simulators, a lot of them seem to be on microcontrollers rather than on Windows (the top result for "PDP-11 emulator" is a JavaScript program to be fair). I wonder why? My guess: microcontrollers are the preferred platform for the kind of people that love the PDP-11 enough to run emulators of this computer.
Well to me it felt like a real challenge, something that would be difficult to do. Because of the resource constraints. Eventually the difficulty was that I was not familiar with the PDP11 platform and not the embedded device (ESP32 SDK is very easy to work with).

Ironic! :)

One of the most famous Chess programs of the 1970s, Belle, was written on a PDP-11 by the famous Ken Thompson.

Here are some more PDP-11 programs - is yours on the list?
https://www.chessprogramming.org/Category:PDP-11
I'm not sure yet. I'm actually trying to figure that out :-)
I did some grepping through the source-code but could not find any details.
The readme says "This program is not the one that won the U. S. championship.".
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Jim Ablett
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Re: PDP11

Post by Jim Ablett »

More info in this old thread from Hiarcs forum > https://hiarcs.net/forums/viewtopic.php?t=8343&start=15

Jim.
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flok
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Re: PDP11

Post by flok »

Jim Ablett wrote: Thu Jun 20, 2024 5:13 pm More info in this old thread from Hiarcs forum > https://hiarcs.net/forums/viewtopic.php?t=8343&start=15

Jim.
Ah! So it is 2.11BSD. Cool. Did not realise there is a man-page for it :oops:
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Jim Ablett
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Re: PDP11

Post by Jim Ablett »

For anyone who want to try Ken Thompson's BSD chess I have compiled the Python PDP-11 emulator available here >
https://github.com/amakukha/PyPDP11
into a native windows executable.

https://drive.proton.me/urls/NRNVS5XPT4#1FLBQe8Xi2gS

Run the program, press the 'Start routine' button on the interface then type the following commands in the unix terminal (click image to enlarge) >

Image

While playing press enter key to display the board.

Jim.
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Jim Ablett
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Re: PDP11

Post by Jim Ablett »

Here is the C src code to the chess program >

https://www.retro11.de/ouxr/211bsd/usr/ ... pdp/chess/

Now if only we could port it to compile/run on modern systems.

Jim.
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hgm
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Re: PDP11

Post by hgm »

That will be hard, as part of it is written in PDP-11 assembly language.