Some Assembly Required
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.
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.
Tomu is a super cheap Open Source Hardware 24 MHz ARM computer with 8 KB of RAM and 64 KB of ROM that fits into your USB connector! Of course I had to put Commodore 64 BASIC on it, which can be accessed through the USB-Serial port exposed by the device.
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 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.
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
This is the video recording of “The Ultimate Apollo Guidance Computer Talk” at 34C3. If you think it is too fast, try watching it at 0.75x speed.
After The Ultimate Commodore 64 Talk (2008) and The Ultimate Game Boy Talk (2016), my third talk from the “Ultimate” series will take place at the 34th Chaos Communication Congress at Leipzig (27-30 Dec 2017):
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.
The text screen of the Commodore 64 has a resolution of 40 by 25 characters, based on the hardware text mode of the VIC-II video chip. This is a step up from the VIC-20’s 22 characters per line, but since computers in the professional segment (Commodore PET 8000 series, CP/M, MS-DOS) usually had 80 columns, several solutions – both hardware and software – exist to allow 80 columns on a C64 as well. Let’s look at how this is done in software! At the end of this article, I present a fast and full-featured open source implementation with several different character sets.
Many reverse-engineered versions of “KERNAL”, the C64’s ROM operating system exist, and some of them even in a form that can be built into the original binary. But how about building the original C64 KERNAL source with the original tools?
This is the video recording of “The Ultimate Game Boy Talk” at 33C3.
I will present “The Ultimate Game Boy Talk” at the 33rd Chaos Communication Congress in Hamburg later in December.
The GEOS operating system managed to clone the Macintosh GUI on the Commodore 64, a computer with an 8 bit CPU and 64 KB of RAM. Based on Maciej Witkowiak's work, I created a reverse-engineered source version of the C64 GEOS 2.0 KERNAL for the cc65 compiler suite:
Major GEOS applications on the Commodore 64 protect themselves from unauthorized duplication by keying themselves to the operating system's serial number. To avoid tampering with this mechanism, the system contains some elaborate traps, which will be discussed in this article.
In mid-1990, the floppy disk of special issue 55 of the German Commodore 64 magazine "64'er" contained the "Amica Paint" graphics program – which was broken beyond usefulness. I'll describe what went wrong.
The PETSCII character encoding that is used on the Commodore 64 (and all other Commodore 8 bit computers) is similar to ASCII, but different: Uppercase and lowercase are swapped! Why is this?
There are many MOS 6502 cross-assemblers available. Here’s a new one. Or actually a very old one. “Macross”, a very powerful 6502 macro assembler, which was used to create Habitat, Maniac Mansion and Zak McKracken, was developed between 1984 and 1987 at Lucasfilm Ltd. and is now Open Source (MIT license):
The Hypervisor.framework user mode virtualization API introduced in Mac OS X 10.10 (Yosemite) cannot only be used for toy projects like the hvdos DOS Emulator, but is full-featured enough to support a full virtualization solution that can for example run Linux.
Microsoft BASIC for 6502 exists digitally in source form – the older version of the Intel 8080 CPU only exists on paper though: as a printout in the archives of Harvard University. Some snippets of the code are public though: