C64 Keyboard Layout for the C16
The Commodore 16 is an interesting machine, but the keyboard layout is infuriating. The cursor keys are at an awful place and… and… and… well, it just isn’t the C64 layout I’m used to!
Analyzing the ROMs of Third Party Disk Drives for the C64
Most Commodore 64 users had a 1541 disk drives, but there were always also third part options. Most of them claimed full 1541 compatibility, which sounds impossible without using the same ROM. Let’s analyze the ROMs of some third party drives!
Reconstructing the Unreleased C128 ROM Update
The C128 source dump over at zimmers.net that appeared recently contains source for a version 2 kernel, which was never released. The known versions are 0 and 1. Let’s see whether we can reconstruct the ROM image!
Original Commodore Source Code Collection
Over the years, the ROM source code of many Commodore computers and peripherals has appeared. I have been collecting them in a git repository here:
Commodore Peripheral Bus: Part 3: Commodore DOS
In the series about the variants of the Commodore Peripheral Bus family, this article covers the common layer 4: The “Commodore DOS” interface to disk drives.
Commodore Peripheral Bus: Part 2: Bus Arbitration, TALK/LISTEN
In the series about the variants of the Commodore Peripheral Bus family, this article covers the common layer 3: the bus arbitration layer with the TALK/LISTEN protocol.
Commodore Peripheral Bus: Part 1: IEEE-488
In the series about the variants of the Commodore Peripheral Bus family, this article covers the lowest two layers (electrical and byte transfer) of the IEEE-488 bus as found on the PET/CBM series.
Commodore Peripheral Bus: Overview
The well-known Serial Bus (aka Serial “IEC” Bus) of the Commodore 64 that connects to disk drives such as the 1541 is just one variant of a whole family of busses and protocols used by the line of 8 bit Commodore machines from the PET to the C65. This is the first article of a multi-part series on the Commodore Peripheral Bus family.
Das neue Commodore 64 Intern Buch [PDF]
Archiving C64 Tapes Correctly
It’s pretty simple to archive Commodore 64 tapes, but it’s hard if you want to do it right. Creating the complete archive of the German “INPUT 64” magazine was not as easy as getting one copy of each of the 32 tapes and reading them. The tapes are over 30 years old by now, and many of them are hardly readable any more.
INPUT 64 Magazine Complete Archive
The complete archive of the German Commodore 64 magazine INPUT 64 (PDF, tapes, disks) is now available here.
Video of a Real C64 Defragmenting a Disk
Here is a 21 minute video of defrag1541 running on a real Commodore 64 – with sound!
A Visual Defragmenter for the Commodore 64
For decades, PC users have been able to relax by watching the computer defragment a disk. Now C64 users can do the same! Introducing “defrag1541”, a disk defragmentation tool for C64 and 1541.
C64-Artikel in der c't Retro 2018
This post is about articles I wrote for the c’t magazine in German language. The post is therefore in German.
Repairing a Commodore 1084S Power Switch
The power switch of the Commodore 1084S tends to break easily. To replace it, you will need a standard “Preh TV3” switch (which can be found online), a screwdriver, a soldering iron, desoldering braid, and some basic soldering skills.
A Minimal C64 Datasette Program Loader
The Commodore Datasette recording format is heavily optimized for data safety and can compensate for many typical issues of cassette tape, like incorrect speed, inconsistent speed (wow/flutter), and small as well as longer dropouts. This makes the format more complex and way less efficient than, for example, “Turbo Tape” or all other custom formats used by commercial games. Let’s explore the format by writing a minimal tape loader for the C64, optimized for size, which can decode correct tapes, but does not support error correction.
Making Of "Murdlok", the new old adventure game for the C64
Recently, the 1986 adventure game “Murdlok” was published here for the first time. This is author Peter Hempel‘s “making-of” story, in German. (English translation)
Murdlok: A new old adventure game for the C64
Murdlok is a previously unreleased graphical text-based adventure game for the Commodore 64 written in 1986 by Peter Hempel. A German and an English version exist.
Commodore KERNAL History
If you have ever written 6502 code for the Commodore 64, you may remember using “JSR $FFD2” to print a character on the screen. You may have read that the jump table at the end of the KERNAL ROM was designed to allow applications to run on a all Commodore 8 bit computers from the PET to the C128 (and the C65!) – but that is a misconception. This article will show how
62 Reverse-Engineered C64 Assembly Listings
Between 1992 and 1995, I reverse engineered Commodore 64 applications by printing their disassemblies on paper and adding handwritten comments (in German). These are the PDF scans of the 62 applications, which are 552 pages total.