BlathrWayne Lorentz

Showing blathrs with the tag “KIM-1.”

♫ Chess nuts boasting in an open foyer ♫

Friday, December 23rd, 2022 Alive 18,868 days

MicroChess on a KIM Uno hooked up to a MacBook Pro

I almost beat a computer at chess today. Almost.

I've been playing chess against computers for four decades now, and have never beaten one. Not even once. Not even on “novice” levels. If a chess board had pieces more worthless and expendable than pawns, I would be one of those pieces.

But I keep playing. Atari 2600 Video Chess? Kicked my ass. Sargon Ⅱ on a Commodore 64? Took my lunch money and gave me a wedgie. Battle Chess on an IBM XT? Bought me flowers, took me to dinner, brought me home, kissed my hand and then didn't call me the next day.

Tonight I did something I have never done before: I managed to “check” a computer opponent.

The opponent was MicroChess on a KIM Uno, the modern-day incarnation of the old MOS KIM-1 machine.

The KIM did eventually beat me, but for once it wasn't the sort of Gulf War shock-and-awe defeat I'm used to.

I got the KIM because I nurse a fascination with the early days of computing, and because I found out that one can be built for under $20. That's another of my fascinations: Ultra-cheap computers.

My KIM Uno, happily letting me know that white pawn 0F moved from space 13 to space 33. I later housed it in a cardboard box

The KIM Uno is a good way to get a taste of what it was like to compute in 1976. But it's not a faithful reproduction. It's more like a tribute than a recreation. The KIM software runs on a miniature single board computer, and has been modified in ways that make a lot of concessions to the limitations of the Arduino side of its split personality.

There are a lot of web sites on the internet that talk about the Uno, but it's clear that the people who blog about this machine put the parts together, poked in about six instructions of 6502 assembly, and then moved on to other things. If they had stuck with the KIM Uno, there would be an extensive library of modern software available for it the way there is for other new models of old computers.

One sure sign that nobody has ever used a KIM Uno for anything other than a minor plaything is that nowhere on any of the web pages flogging it do the writers mention battery life. I surmise that none of them used it long enough for that to be a concern.

The Kim Uno's primary problem is that it lack expandability. One of the greatest assets of the original KIM-1 was that it could be expanded in many ways. You could add memory. Add storage devices. Add circuits and relays and printers and terminals and pretty much anything the hobbyist could imagine. The KIM Uno leans on the Arduino's built-in serial port, and that's about its only connectivity. But even that serial port is fixed at a speed and parameters that make it incompatible with a number of era-appropriate terminals.

There is an expansion port of sorts on the KIM Uno, but it isn't documented. There's a single picture on the internet of the KIM Uno driving a small OLED display, but no information about how to do that. And worse, the KIM Uno machine driving the display isn't even running the KIM-1 ROMs. It's being used to emulate a COSMAC ELF.

To summarize: unlike the KIM-1, the only thing the KIM Uno is good for is to play chess. But on the other hand, the KIM-1 cost the equivalent of $1,300 today dollars, while the KIM Uno can be had for less than $12 in parts. But with that reduction in price comes a reduction in possibilities. And the whole reason people got into computers in the 1970ʼs was because at the time, we thought the possibilities of technology were endless.

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