[chbot] More on the PDP-8

[Brendan McNeill]

Hi Everyone

I recently obtained my Amateur radio licence which is where I met Mark Atherton.  Mark circulated my restoration effort on the PDP8 computer: https://pdp-8.nz <https://pdp-8.nz/> (which is hosted on a RaspberryPi at home) to all of you at the Robotics group.  He also suggested I join the group list and put out a request for assistance that one or more of you may be interested in helping with. This was prompted by a response Mark received from a gentleman named Richard who had previously programmed one of these computers using Focal-8 in the early 1970’s, and what a great decade that was!

While I have the machine running, and I’m able to load various languages including Focal-8 and Focal-69, and most probably a form of BASIC, there is very little by way of application software available for the machine, after all, it was more than fifty years ago when it was manufactured!

There is a chess program that someone has written in machine code.  A very worthy effort indeed.  However, I had an idea for a relatively simple but interesting (to me at least) application that generate prime numbers and print each one it found on a new line.  I’m more of a hardware and systems programmer than an applications programmer, although I guess being confined to base for a few weeks I could apply myself to the task.  I’m sure however that there are many of you out there more gifted than me in this department, and who might like to apply themselves to creating the necessary code in Focal. (preferably Focal-69 as I already have a copy).

The Focal manual can be found here:

http://homepage.divms.uiowa.edu/~jones/pdp8/focal/focal69.html <http://homepage.divms.uiowa.edu/~jones/pdp8/focal/focal69.html>

If you wanted, we could make it into a competition to create the program in the least lines of code?  That’s up to you.  However if you were interested I could test the programs and publish the winning code to this list?

I’m really just interested in seeing the machine do something beyond running diagnostics and playing chess. If you have more interesting programming ideas you would like to run with that’s fine too. I’m more than happy to accept machine code applications as well.

Long term I’d like to get this system (and others I have around) into a museum of some kind, but that’s down the track. I appreciate that we are confined to base at present, but if any of you are interested in seeing the machine close up, or keying in your program personally, then you have an open invitation to come by.  I live on Idris Road not far from the club rooms, and will provide my address to anyone who asks.

So coders, young and old(er) are we up for the Prime Number Generator challenge?  There are several algorithms available on the net to help get you started.  Feel fee to contact me directly on the email address below.

Kind regards
Brendan McNeill

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brendan at mcneill.co.nz
+64 21 881 883




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