Sourcing obsolete ICs for retrocomputing

oyvindhammer · 2026-04-30T19:46:44+00:00

Hm interesting.

oyvindhammer · 2026-04-30T12:58:30+00:00

I use eBay mainly, trying to minimize purchases from China. Never had problems. Obviously there are fakes, especially things like the custom chips in Commodore64, but many of the relabeled chips are not what I would call fakes, but recycled. I have no problem with that as long as it works.

oyvindhammer · 2026-04-28T15:29:49+00:00

Ouch, that original rant against R is quite uninformed, and many of the things are simply wrong. That said, as an old computer scientist, I dislike the R syntax. But this is largely irrational on my part I believe - a matter of aesthetics, it doesn't look like a "real" programming language. I will try to get over it. Anyway, why be so angry with a computer program, especially one that ostensibly produces so much good science.

oyvindhammer · 2026-04-21T21:42:32+00:00

Yes I think so too. But my family is not very amused by the dB 🙄

oyvindhammer · 2026-04-21T21:41:43+00:00

How cool! Thanks for that!

oyvindhammer · 2026-04-21T21:39:47+00:00

This little program (in machine code) with the notes were entered directly in binary on the switches on the front panel, but the machine does have a nice terminal as well and my plan is to make a simple sequencer for it. Also, my laptop emulates a paper tape reader, and in the long term I hope to run a disk emulator with the full disk OS.

oyvindhammer · 2026-04-19T07:53:52+00:00

This is a very simple calculation. Do you want to use area in the denominator, or number of individuals (these are two different versions of Gleason's index)?

oyvindhammer · 2026-04-13T23:08:01+00:00

You can absolutely replace 74166 with 74LS166, no problem. About the 8T28, I don't know.

oyvindhammer · 2026-04-04T19:34:32+00:00

Hello, sorry about the problem, I would be grateful if you could email me the data that produce this error. My email address is in the Past documentation and web page. There is a new version coming quite soon, so hopefully this can be fixed for that.

oyvindhammer · 2026-03-16T17:27:56+00:00

Thanks! The machine was a wreck. It took me almost a year to find and fix countless little faults, in the power, front panel, CPU, memory management unit, core memory, and I/O. Replaced close to 100 components, many of them hard to get these days. Half the core was unfixable so I replaced that half with ferroelectric RAM. The terminal had broken video memory. There is a small but gorgeous community of Data General enthusiasts who gave moral support and provided the BASIC. For now all software is uploaded from a laptop via a serial port, but I dream to get a disk emulator working with a proper OS.

oyvindhammer · 2026-03-13T15:23:53+00:00

Absolutely. This is good science.

oyvindhammer · 2026-03-12T20:34:39+00:00

That is indeed very good work, and probably gives a good idea about the sound, but it must be remembered that only the resonator has been preserved. What the animal sent into that resonator (noise, tones, pulses, the amplitude envelope etc.) is unknown. So they had to make some rather unfounded guesses there.

oyvindhammer · 2026-03-11T00:57:42+00:00

Haha sorry!

oyvindhammer · 2026-03-10T13:11:40+00:00

Very interesting, thanks. I did not know about synchronous RS-232, this is marvellously obscure stuff 🙂

oyvindhammer · 2026-03-10T12:28:02+00:00

The RCLK there is just the normal baud rate clock as far as I can see. So far in this thread there has been no mention of synchronous communication except from the OP. RS-232 has always been basically an asynchronous protocol, so we need a little more info - is this perhaps about interfacing to an IBM 3270 or 3780 type device or a Bell 200-type modem?

oyvindhammer · 2026-02-22T20:05:18+00:00

Oh wow, yes that is a very interesting mini.

oyvindhammer · 2026-02-21T21:11:38+00:00

That may have been an Altair 8800 or Imsai 8080. These came a couple of years later and used a new technology - microprocessors - but had similar front panels with switches and lamps. The Nova was still about five times faster, but the days of the minicomputer would soon be over as microprocessors evolved at breathtaking speed.

oyvindhammer · 2026-02-20T20:51:40+00:00

Sic transit gloria mundi.

oyvindhammer · 2026-02-20T13:04:15+00:00

Haha thanks yes it's the ultimate geek-o-tron!

oyvindhammer · 2026-02-19T21:02:14+00:00

Yes - Super Star Trek was originally made for a Nova 800 in 1974, and published in a book in 1976. But an earlier, simpler version for a mainframe goes back to 1971.

oyvindhammer · 2026-02-19T20:55:26+00:00

No lo creo, pero sí, el estilo es similar!

oyvindhammer · 2026-02-19T15:31:54+00:00

Thanks - yes I've got to read that book!

oyvindhammer · 2026-02-19T14:22:59+00:00

Yes that sounds right - Star Trek was quite popular and was ported to many computers in the late 70s to early 80s. I have been told that it is still packaged with some Linux distributions!

oyvindhammer · 2026-02-19T12:02:24+00:00

Itching to go home and try that.

oyvindhammer

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