My 1976 KIM-1 | Hacker News Reader

My 1976 KIM-1

blog.jgc.org

96 pointsjgrahamc31 comments

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Holy cow. It is incredible how versatile this little thing is. I wonder if anyone has succeeded building a personal computer out of it, with keyboard and tape.

Yes. This is exactly what happened.

The KIM-1 (Keyboard Input Monitor) was created by Chuck Peddle at MOS Technology, which later was bought by Commodore, so the MOS Technology KIM-1 became the Commodore KIM-1. (Source: https://en.wikipedia.org/wiki/KIM-1)

Peddle then expanded the KIM-1 into the Commodore PET 2001 with case, monitor, keyboard and tape drive all built in. The 2 KB TIM (Terminal Input Monitor) ROM in the KIM-1 was expanded into the 4 KB KERNAL ROM in the PET. (Source: https://en.wikipedia.org/wiki/Commodore_PET)

Of course, then the PET was upgraded with additional models including the 3032, 4032, 8032, 8096, 8296 and the SuperPET, then the CBM-II series and the Commodore VIC-20, Commodore 64, Commodore 16, Plus/4, Commodore 128 and the unreleased Commodore 65.

I remember many years ago a school teacher let me borrow a book where someone made a robot out of a KIM-1: https://cyberneticzoo.com/cyberneticanimals/1976-mike-microt...

Of course. There are many such examples of homebrew kits with tape and TTY; I routinely use a serial port connection as TTY over the 20mA current loop with my briefcase KIM that also has the tape lines brought out to a 1/4" TRS jack, though uploading binaries over the serial link is more handy for testing. The TVT 6 5/8 was an easy to assemble video board, or the cool kids had an MTU 8K RAM expansion that emitted the contents as a 320x200 composite image.

In fact, the AIM-65 was basically a heavily expanded KIM with a LED screen, printer, keyboard and tape all in one box from the factory.

Trivia bit.

For those that don't know, the Cal Poly Universities at Pomona and San Luis Obispo collaborate on the annual Rose Parade Float.

Back in the day, they would win awards for their motion control and animation work. Much of that work was done down at Pomona.

And the computer they used as the control computer in those early days was the AIM-65.

You like the word 'handy'. It's in the blog post twice and once in your comment here.

I suppose I do, but to make you happy I've changed one use of handy to nifty.

Trivia: handy means 'mobile phone' in Austrian German

It wasn’t 'classichasclass who wrote the blog post…

Not sure if that was ironic, but the Apple I , then Apple II was exactly that. Also the PET.

Sorry, this was before my times and in a land far away. I started with the ZX Spectrum.

Dave's Garage on YouTube has some videos on him aquiring a fairly built out Kim-1 with keyboard and video display IIRC.

I swear I can still recite a bunch of hex for 6502 opcodes, burned in after entering them painstakingly into a monitor program.

The only ones I can remember are A9, 20 and 00.

"The week number for the 6502 is important because apparently 6502s made up to week 26 had faults!"

I thought only the first revision 6502's (1975, in a white ceramic package) had the ROR bug, or are these faults something other than ROR?

In a video from early this year, Eric Schlaepfer claims the ROR behavior in the early 6502's isn't actually a bug, the instruction was consciously left out. I found the explanation interesting:

https://www.youtube.com/watch?v=Uk_QC1eU0Fg

Also of note: datecodes in "wwyy" format. "yyww" is far more common.

Funny thing is (assuming that KIM-1 still works): you buy a brand new computer today. In 5, 8 maybe 10y (if you're lucky) it will be ewaste. Quicker if it's a phone. And chances are by then that KIM-1 will still work. Or be easy to repair. Similar with many machines of that period.

Tech has advanced tremendously. But in some aspects, backwards.

I nearly bought one, but ended up getting a Synertek SYM-1 instead. It was great in its day, and quite capable as a development platform. (I had a terminal connected to the serial port, tape recorder for loading/storing content, added the BASIC ROM and the Editor/Assembler ROM, and doubled the RAM to 8KB.)

https://en.wikipedia.org/wiki/SYM-1

I had an uncle who'd built a KIM-1 clone (Elektor Junior[1]), with a kit from the Indian Elektor magazine. As a kid, he'd never let me touch it. I think it was one of the factors that got me into programming, a few years later.

[1]: https://en.wikipedia.org/wiki/Elektor_Junior_Computer

This was my first computer, too. I have fond memories of programming it in 6502 machine language and saving programs on cassette tape. I still have it, along with the power supply my grandfather built from the specs they provided in the user manual. And it still works!

I own an IASIS IA-7301 which is very similar single board trainer The IASIS is built around the NEC μCOM-80 version of the Intel 8080. The board is attached to a plastic backer that fits into a three ring binder. An entire programming course is included in the binder.

https://www.old-computers.com/museum/computer.asp?c=544

My first was a Commodore VIC-20 (1981, I think), with a machine language monitor module.

It only had 3KB of RAM, so any program of worth was written in machine code.

The VIC-20 actually has 5 KB of RAM but 1.5 KB of that is used by zero page, the stack, the OS KERNAL and BASIC, leaving 3.5 KB of RAM for BASIC or binary programs. The VIC-20 can be expanded up to 40 KB of RAM but 8 KB of that is not contiguous resulting in a maximum of 28,159 bytes free in BASIC.

If I am not mistaken, we had a pratical where we had to use a KIM-1, when I was studying computer science. I guess this was in 1982.

The KIM-1 was my first computer, my Dad got it for me in my Junior year of High School. I had great fun working through the First Book of KIM.

I tried my hand at assorted electronics experiments, but managed to shove 9v into one of the PIO pins, frying it.

I did replace the 6530 chip, but never installed it. I actually still have it somewhere, still in its anti-static foam.

Is this where Woz got his inspiration for the Apple ][ from?

No.

Firstly, he built the Apple 1 with a 6502 before the Apple ][, which was a major improvement on the Apple 1.

He had designed the Apple 1 on paper before the 6502 was available. He had preferred the Motorola 6800 processor but couldn't afford it at $170 ($925 in 2022 dollars). Then when the 6502 came out priced at $20 ($103 in 2022 dollars), he used it instead.

So the KIM-1 had no bearing on the Apple 1 or Apple ][.

Source: https://en.wikipedia.org/wiki/Apple_I

Reminder that the OP has a whole HN-style site for retro:

https://twostopbits.com/news

Aah, the memories! Glad there's emulators for most of these things, anyone can try them out virtually. Of course it ain't the same as pushing buttons on the real thing, but it's still fun!

If you like to push buttons, I have tried these 2 options:

1, Kim Uno: https://obsolescence.wixsite.com/obsolescence/kim-uno-get-or... - it is basically an Arduino emulating all the hardware of the KIM-1. Battery-powered, and fits in your (large) pocket.

2, PAL-1 replica board: https://www.tindie.com/products/tkoak/pal-1-a-mos-6502-power... - uses more-commonly-available parts than an original KIM-1 (e.g., 65C02 instead of the original NMOS part, and a RIOT+EPROM, instead of a mask-programmed RRIOT) but still a lot of fun to solder together. The creator has also made an expansion port and lots of gadgets to attach to it, including an optional backplane. Works with a DE-9 serial port! I have connected mine to a Digital VT520 serial terminal, among other things.

PAL-1 is excellent.

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