Inside geoWrite – 1: The Overlay System
geoWrite is a WYSIWYG rich text editor for the Commodore 64 GEOS operating system, which runs with a total of just 64 KB of RAM. In the series about the internals of geoWrite, this article discusses how it manages to fit 52 KB of code into the available 23 KB of application RAM.
CMDR-DOS: Commodore DOS on FAT32
All disk drives connected to the Serial Bus of a Commodore 64 speak the Commodore DOS protocol, from the popular 1541 5.25″ drive to the modern sd2iec SD card interfaces. CMDR-DOS is a new and open source implementation of the Commodore DOS protocol, using SD cards with the FAT32 filesystem and supporting advances features like partitions, subdirectories and timestamps – and running on a 65c02!
FAT32 Filesystem for the 65c02
We are presenting the (to our knowledge) first full-featured open source library for 65c02 CPUs for accessing FAT32 formatted disks.
Building the Tynemouth Mini PET
Ultimate Commodore Charset / PETSCII / Keyboard Reference
Another addition to the The Ultimate C64 Reference: We’re adding character sets, PETSCII codes and keyboard layouts – supporting eight different Commodore computers.
Ultimate C64 KERNAL API Reference
The Ultimate C64 Reference is growing again: This time, we’re adding the KERNAL API reference – as always, in eleven different versions side-by-side.
Ultimate C64 Memory Map
The system software of the Commodore 64 has been extensively reverse-engineered. Next to disassemblies of the ROM, several “memory maps” have been published: tables that document system variables in the first kilobyte of RAM, and how to tweak the system software with PEEK and POKE. Now, I’m presenting the Ultimate C64 Memory Map: A C64 memory reference that shows eight sources side-by-side.
Typos in the C64 Programmer’s Reference Guide: C3PO or C3P0?
The Commodore 64 Programmer’s Reference Guide contains a memory map with a complete description of the zeropage and system variables used by KERNAL and BASIC, but now that we have the original source, we know there are three typos in this table.
Dumping MiniDisc Media
If you have music on a collection of MiniDisc media and want to finally copy the data off onto modern media (or the cloud!), here are simple instructions for some different solutions:
The Ultimate Acorn Archimedes Talk [video]
Matt Evans presented “The Ultimate Acorn Archimedes Talk”, the 8th talk in the “Ultimate Talk” series, at the 36th Chaos Communication Congress (36C3).
Commander X16: Philosophy and Specification
I recently got involved in the Commander X16 project. I would like to give an overview of the project and the vision behind it from my perspective.
NES and SNES Controllers on a 6502 (like the C64)
NES and SNES controllers support 8 to 12 buttons with only three data pins (plus VCC/GND). Let’s attach them to a C64 – or any 6502-based system!
The Apollo Guidance Computer [video + slides]
I re-did an updated version of my part of the Ultimate Apollo Guidance Computer Talk at VCF West 2019.
Visualizing Commodore 1541 Disk Contents – Part 2: Errors
We have previously visualized the physical layout of C64/1541 disks. In order to understand the encoding and potential read errors, it is more useful to visualize the disks sector-by-sector.
Commodore “Video Supergame 64” Bundle
The “Video Supergame 64” is a Commodore 64 bundled with a joystick and three games on a cartridge, sold mainly in Germany in 1988/1989. Here are some pictures.
Dumping Commodore 64/1541 Disks with Errors
Many old Commodore 64/1541 disks have read errors, but this doesn’t mean the data isn’t recoverable – with the right nibtools settings and some cleaning.
Commodore “Magic Voice” Cartridge for C64
“Magic Voice” is an expansion cartridge for the Commodore 64 that can speak 235 predefined words. Here are some pictures.
TopDesk 1.3 GEOS64/128 Original Source
Thanks to Falk Rehwagen and Jürgen Heinisch, the original source of the TopDesk file manager for the GEOS operating system of C64/C128 is available.
Tynemouth Minstrel ZX80 Clone Kit
I have previously shown an unassembled Sinclair ZX81 Kit that could be bought in the early 80s. Today, it is possible to buy a clone of the ZX80 from Tynemouth Software. Here are some pictures.