Many sources of the KIM-1 monitor are floating around. All typed in from the user manual, most are not identical to the original text. None deliver the real KIM-1 ROMs, they fail with filling unused bytes with FF. And the text and comments are incomplete, wrong or made up.

So in June 2026 I have typed in the source of the KIM-1 monitor as it is listed in the User manual. Every line has the same line number, all text including comments is as in the paper listing. The listing is also paged as the original. Converted to a modern MOS Technology assembler format (I used TAS32), that delivers the exact ROM binary (including those 00 filler bytes!) as dumped from the real 6530-002 and -003 by me.

KIM-1 Monitor source, listing and binaries and TASM32 archive

More on the KIM-1 ROMs here.

MOStermind is an implementation of the Mastermind board game for the KIM-1 computer.
Developed by HKZ.

It’s written in 6502 assembly using DASM assembler and MAME as developing tools.

You can download it here

How to play

The game follows the basic rules of mastermind: the codemaster generates a hidden code and you have to guess it in a limited number of tries, while the codemaster gives you a report on how much you got right for each guess.

The codes are be composed by 4 symbols, each symbol can be one of the following 8 characters: `A`, `B`, `C`, `D`, `E`, `F`, `G`, `H`. Note that a character appearing multiple times in a code is perfectly valid.

After you type in the 4 character code and press `RETURN`, the codemaster will analyze your guess and report the result using 4 symbols:

– `O` indicates that one symbol is both the right character and at the correct spot
– `*` indicates that a symbol is a character that appears in the code, but is in the wrong place
– `.` Indicates that a character is not present at all in the code

Note that these are **NON POSITIONAL**, and they’re just shown in order of precedence: first `O`, then `*`, then `.`. They bear no information on which of the characters is right. You’ll have to find that yourself.

In case you want to cancel a guess before submitting it (to avoid wasting a try), you can press `BACKSPACE`. The guess submission will be aborted, no analysis will be performed and you’ll be able to submit a new guess.

Does it run on the KIM-1 Simulator? YES!

You only have to set the FOCAL_V3D break setting in the Settings.

Again Eduardo Casino has enhanced the KIM-1 Simulator V2.3.0 after adding the K-1103 and Corsham SD-Shield with CODOS and CP/M-65 operating system in V2.0:

Version 2.2 and 2.3:

– The Console has now a complete VT100 emulation with color and the DEC Special Character set
– The console supports cut and paste text with the mouse (very handy to dump a papertape into the KIM-1)
– The K-1008 Visable Memory emulation has become blazing fast
– All settings are saved between sessions

A KIM-3B is a 8K bytes memory expansion made by MOS Technology (already part of Commodore then) for the KIM-4 motherboard.

I recently acquired a good looking KIM-3B myself. Nothing new, all is already known about it. Now with photos made by myself!