https://blog.jgc.org/2023/11/my-1976-kim-1.html
Some years ago I wrote about programming a KIM-1 in 1985. By that time the KIM-1 was old, and definitely not state of the art. After all, it was released in 1976.
But it's a machine I enjoyed programming (which required punching in code via the hex keypad, or, if you were lucky, connecting a terminal (via a 20mA current loop designed to talk to an actual Teletype) to it and using the very basic monitor program). The KIM-1 could also interface to a paper-tape reader/punch and a cassette for storing and loading programs.
I have a tiny collection of machines that matter in my personal computing history: a Sharp MZ-80K, a Research Machines 380Z, a Research Machines 480Z, my original BBC Micro and a KIM-1 (that's a picture of my machine above). The (fully working) KIM-1 was made in 1976 and is serial number 2,793. It's still sitting in its original packaging:
(Score: 5, Informative) by VLM on Wednesday November 08 2023, @09:50PM (1 child)
That's a popular board for modern (and not so modern) builders. I own several different ones. Some use modern components and copy the board, usually professionally laid out to be much smaller. Some emulate the entire works in a microcontroller which is kind of boring although I respect the extremely small size.
I just checked WDC's website and they're still selling brand new 6502 chips, along with vastly expanded chips in the family. If it works, don't fix it, still applies in some areas of technology. Its a pity WDC doesn't sell KIM-1 SBCs, they sell many other SBCs and dev kits.
I grew up with 6809s and Z80s so maybe my second childhood was 6502 LOL so I have a fair amount of 6502 "stuff". At the time I was "spoiled" by the vastly superior 6809 and Z80 although now the 6502 has its charms.
(Score: 3, Interesting) by RS3 on Wednesday November 08 2023, @10:55PM
I have a very original KIM-1. They're going for pretty big $ on ebay. Maybe you'd want to think about making a 6502 SBC, maybe? I don't know about the monitor ROM copyright, but it's probably not too difficult to write something similar.
(Score: 2) by turgid on Wednesday November 08 2023, @11:14PM (1 child)
Back in the early 90s I picked up a "piece of old rubbish" that was going in the skip. I have no idea what company made it, but it had the following spec. It was a Z80 system at 2MHz with about 64k or RAM. The system had a console (green screen) connected with a 25-pin DIN plug. It also had an external dual 8" floppy drive unit which weighed a TONNE! Apparently it ran a multi-user variant of CP/M (supplied on disk) and could support up to four concurrent users on RS-232 in addition to the console.
It came with the OS and some sort of BASIC interpreter. I remember playing about with it and being utterly astounded at how primitive it was. On one of the disks there was a BASIC game that asked you to type in your name. It echoed it in reverse...
I never found out what make it was or anything else but my father made me dispose of it. A multi-user Z80 system. When could Windows NT support multiple users?
I refuse to engage in a battle of wits with an unarmed opponent [wikipedia.org].
(Score: 5, Interesting) by owl on Thursday November 09 2023, @01:34AM
This was nothing odd in the early 90's. In 1982-1983 my high school's "computer lab" was some kind of similar level "box" with either four or six serial terminals attached for for or six simultaneous users. If memory serves it was CP/M and 8" floppies too. These were simply scaled down mainframe/mini's in smaller form factors. The reason things were done this way was generally cost. Easier to justify to the bean counters if the cost of the computer was amortized over four or eight seats.
In fact, the "revolution" in "personal computer revolution" was the very idea that one could have a "personal computer" all of one's own. Lots of folks who's first introduction to computers was with the Apple II, Atari's, Commodore 64's, TI 88/4's, PC's with DOS had no idea that they were using a "box" that just a few years earlier would have been shared among four or eight or sixteen simultaneous users. Prior to the "revolution" it was unthinkable to not share a computer amongst plural users. They were just too expensive to devote a whole "computer" to just one person.
Of course, by the time I became eligible to take the "computer class" (it was only offered for 11'th and 12'th grades) in the fall of 1983 they had swapped out for a room full of Apple II's networked to a single Corvus hard disk for "network storage". Of course each Apple also had a floppy, so most of us stored our stuff on our own disks rather than on the "central disk".
(Score: 1, Interesting) by Anonymous Coward on Thursday November 09 2023, @01:22AM
I learned to code assembly on a Rockwell AIM 65 [oldcomputers.net]. We actually used them in an undergraduate physics class. The prof who taught it was very advanced into automation. We used the AIM 65 and a bunch of red/yellow/green LEDs to make a traffic light system for a complicated traffic intersection, including pedestrian signals and switches. It was one of the best computer classes I ever had, and it was taught as an advanced physics class!
(Score: 5, Interesting) by SnorkleZ on Thursday November 09 2023, @02:37AM
I ordered the Kim-1 evaluation kit when I was in college. My only prior exposure to assembly code was some recreational coding for the CDC Cyber-74 - using its Compass assembler with 60 bit words, working in octal was very different from keying in 6502 machine code in hex on the Kim-1! I grew to love the simplicity and power of the 6502 instruction set and memory mapped i/o, which inevitably led to my extreme dislike for bloated microcoded architectures with i/o instructions and indexed memory. And don't get me started on my reaction to object-oriented programming. ;-)
I never used the 20 mA current loop, had forgotten it had that. I did have a Model 15ASR Teletype, but that was 60 mA, and Baudot code instead of ASCII. Later built a Don Lancaster TV Typwriter but that was for use with my 300 baud modem. So I only interacted with the Kim-1 using the hex keypad. Some of the op-codes are still burned into my memory - 4C is JMP, I think 20 is JSR and 60 is RTN, or that may be backwards. Entering machine code in hex sounds awful but I much preferred it to typing Fortran into an 026 keypunch machine.
My best project was when I built transistor interface circuitry to wire the Kim-1's parallel port into the frequency selection diode matrix board of my Icom 22S two-meter FM ham radio, turning it into a scanner. What fun!
I eventually got an S100 expansion kit which allowed me to build and connect a Godbout kit 8k memory board. Oh the thrill of having such a massive amount of ram to work with! Soldering 64 2101 memory chips into the 8k ram board was quite a job, over 1,000 solder connections. A friend gave me a 4k board as well, so I had 12k to work with!
The microcomputer industry was so dynamic in those days with many players, like IMSAI, Cromemco, SOL and many many others. So sad when IBM, Intel and Microsoft kind of killed it all. At least the Amiga came along and livened things up again for a while.
Thanks for bringing memories of those good times back!
(Score: 2) by pdfernhout on Sunday November 12 2023, @12:39AM
What I just posted there:
Hi John,
Great post -- especially with all the pictures including the box and manuals. Thank you for it. Brings back memories.
A KIM-1 was my first real computer at around age 13 or so -- moving beyond digital logic circuits I had previously built, mostly with Radio Shack ICs, and simpler things before that with switches and lights and such.
I was interested in robotics and had built a robot controlled directly by buttons. I had later seen the KIM-1 mentioned in "How to build a computer-controlled robot" by Tod Loofbourrow and wanted to build something computerized.
My father helped me buy it from a small walk-up computer store back then and also build the power supply for it with a transformer he had.
I never fully understood the KIM-1 back then, nor did I put it into a robot -- but I started learning the beginnings of machine language / assembly code with it.
I ultimately sold the KIM-1 (and the power supply) to a high school teacher on Long Island for their computer course to get the money to put towards a Commodore PET (brokered by another high school teacher, Jack Woelfel, who sold me the PET).
I understood the PET a lot better, in part from experience with the KIM-1 (and also playing around with TRS-80s in Radio Shack stores). I then hooked a PET up to robot as shown in a picture on my personal website -- but I might not have gotten there as quickly without the KIM-1 start.
Learning from the KIM-1 (with its simple "monitor" software and single stepping mode) also let me quickly understand the CARDIAC (CARDboard Illustrative Aid to Computation) tool used in high school to help teach computing. From there that helped me understand virtual machines better which led to me writing one as an experiment in college -- and feeling comfortable with them for IBM Mainframes and Smalltalk and Java and so on.
KIM-1 roots also helped me in picking up Forth and later C quickly.
And KIM-1 roots also helped me in writing a video game in assembler for the Commodore VIC that helped pay for college.
Would be nice to still have the KIM-1 around, but it was the right choice for me at the time to upgrade, sigh. Nice that there are browser-based KIM-1 emulators around (even one to show the transistor logic states change on the board).
--Paul Fernhout (pdfernhout.net)
"The biggest challenge of the 21st century is the irony of technologies of abundance in the hands of those still thinking in terms of scarcity."
P.S. Saw your post referenced on Soylent News.
The biggest challenge of the 21st century: the irony of technologies of abundance used by scarcity-minded people.