Usurpator II Chess for the 6502

Usurpator Chess for the 6800 and 6502, a book by H.G. Muller

A small but capable chess playing program. Source published in the book for AIM 65.
Typed in again in march 2025 and adapted for the KIM-1.

Programs ready to run, AIM 65 and KIM-1 versions, with binaries and sources in modern 6502 assembler.

Q-Chess 1.0

Q-Chess 1.0 is a chess program for the KIM-1, from around 1980. The programs requiresa a memory expansion of 8K at $2000.
The chess board is displayed at a TVT-6 (Don Lancaster) video display alongside the KIM LED Display and Keypad.
In 1981 Fer Weber, a member of the Dutch KIM User Club published an adaptation to use the program with a (video)terminal attached to the KIM TTY interface in the Dutch magazine the KIM Kenner Issue 17.
Binaries on tape and the documentation of Q-Chess were acquired in 1981 from Fer.
In March 2025 Hans Otten translated the source of the adaptations from Dutch to English in TASM format.
This makes Q-Chess playable again!

KGN COMAL KIM-1 version

COMAL is an interpreted structured language. A version for the KIM-1, Junior and DIS65 is available, distributed by the KIM Gebruikers Club Nederland as KGN COMAL in the 80ties.
KIM-1 version March 2025 by Hans Otten.

KGN COMAL V1 for the KIM-1 and clones, Elektor Junior and DOS65.

A product distributed and adapted to the Junior by the KIM Gebruikers Club The Netherlands in 1985-1987.
KGN COMAL V1.0 is for the enhanced Elektor Junior.
KGN COMAL V2.1 is for the DOS65 system.

In 2015 I saved KGN COMAL 1.0 and 2.1 binaries from Junior tapes and DOS65 disks.
With DOS65 came a very compact COMAL user manual.
In the Club Magazine KIM Kenner a Amazing Maze program is found.

Based upon these binaries and documents KGN COMAL is adapted to the KIM-1.

MOS Technology documents added


A recently acquired KIM-1, of the first generation (that means, No Revision, the first series!) came with a stash of documents from MOS Technology from 1976.

I have scanned those documents and they are available on this website now.

KIM-1 User Manual First Edition, January 1976
KIM User Manual errata letters for First Edition
MOS Technology Floating point BCD routines
MOS Technology January 1976, Rev 0.
Numbers of six digits BCD Mantissa,
a two digit BCD Exponent and the signs for the mantissa
MCS6532 Design Specification
Published before the first 6532 datasheet
MCS6500 Microprocessor Software Support
Guide for using the MOS Technology Support Software on United Computing Systems timesharing service
Describes the MCS6500 Cross Assembler, Simulator and DMP to ROM programs.
MCS6500 datasheet May 1976
MDT 650 product description
MOS Technology newsletters
Simplifying Conversion from 6800 to 6502
TIM Software development Aid Product description
KIM 2-3-4-5 product descriptions

Warranty card that came with this KIM-1

6530 hardware emulator in FPGA in 40 pin DIP

Imagine a true 6530-002 and 6530-003 replacement , the RRIOTs of the KIM-1

Now with modern FPGAs you van do that: a 40 pin PDIP replacement: the reDIP RIOT is made for that purpose.

Here is the code for the reDIP to make it a 6530-002 or 6530-003:

Github with gateware for Commodore MOS 6530 RRIOT

Since the 6532 is in fact a subset of the 6530 (no ROM, more RAM), it seems not too difficult to make a 6532 replacement this way.

The reDIP RIOT is an open source FPGA board which combines the following in a DIP-40 size package:

Lattice iCE40UP5K FPGA
1Mbit FLASH
5V tolerant I/O
The reDIP RIOT provides an open source hardware platform for 6530 RRIOT / MOS 6532 RIOT replacements.

See here the github for this project

https://github.com/daglem/redip-riot

PAL-2 is now on sale

The longawaited successor of the PAL-1, the PAL-2 is on sale now.

https://www.tindie.com/products/kim1/pal-2-a-mos-6502-powered-computer-kit/

My first look at the PAL-2 is here.

Here the first video by my friend Nils of a working PAL-2:

My PAL-2 #1:

KIM-5 Resident Assembler/Editor available!

MOS Technology, part of Commodore in 1977, not only sold the KIM-1 SBC but added hardware and software as KIM System Products.

Not only hardware, a Motherboard (KIM-4), RAM memory expansions (KIM2, -3, -3B) and a prototype board (KIM-6) but also software, like KIM Math subroutines (KIMath), TIM (RRIOT + document).
This has been documented for quite some time now on this website with photos and manuals.

I have been looking for years for the KIM-5 Resident Assembler/Editor. Manuals on Assembler and Editor are already known. The software, delivered in 3 ROMs of type 6540, on a KIM-5 ROM board was never dumped before, and the existence, besides the pricelist shown here and some advertisements, doubted by many, including old Commodore employees.
Many years I searched on the internet on fora, websites and friends in the retro world, it did not lead to a dump of the KIM-5 ROMs.

A couple of years ago I saw a listing on ebay.de of a lot with a a KIM-5 with ROMs and a KIM-3B board. I was too late to bid. I could not contact the seller or buyer afterwards. But now I knew the KIM-5 did exist, and had some photos as proof.

A year later Stefan Hamann approached me to ask for information on KIM-1 material he bought from ebay. He was the buyer of the lot!
Stefan was so nice to lent me the KIM-5 (and KIM-3B) and the EPROMs he obtained. I have finally a KIM-5 in my hands with ROMs!

The ROMS have been dumped, tested in the (updated KIM-1 Simulator to 1.5.1) and source recreated. The KIM-5 Resident Assembler/Editor is preserved!

Read all about this on the newly organized and enhanced KIM System Products pages.


Resident Assembler/Editor at 9000-A7FF

Different versions of KB9 Microsoft Basic for KIM-1?

MOS Technology 6502, 9 DIGIT BASIC by Microsoft, Copyright 1977. often nicknamed KB9, is an early version of Microsoft Basic adapted for the KIM-1. With 9 digit precision and the Microsoft version of Basic a very usable high-level language for a KIM-1 with 16K extra RAM and a videoterminal or teletype.
I bought my version in 1979, serial number 2167. Tape ID #01, 2000-4260. Start 4067.
It is a version that works around the missing ROR instruction on early 6502 CPU’s.
All versions of KB9 on the internet are from the cassette dump I made in 2006, including the brilliant source version on pagetable. Still have a lot of fun with it as well as all the KIM clone users.
I found a photo of MOS TECH 9 DIGIT BASIC FOR KIM, COPYRIGHT BY MICROSOFT 1977 2000-437D ID #101 ST. 4065 S/N 217 cassette of a much lower serial number.
What is interesting is the higher End address, 437D versus 4260.
Alas no dump of this cassette is known, so this stays a mystery. as is the illegal tape ID 101.

My MSBasic for the KIM-1 cassette

Another MOS TECH BASIC for KIM-1

RNB VAK-1 photos

Thanks to Eric Dennison I can show photos of the RNB Enterprises VAK-1 motherboard.

The large motherboard and the huge case with homebuilt 16K static RAM memory card are representative for the KIM-1 systems then!

Photo by Eric Dennison

Photo by Eric Dennison

The Sorbus computer

A new development! A minimal 65(C)02 system, called Sorbus designed by Sven Oliver Moll (SvOlli).