In this episode of computer archeology, we deconstruct a very interesting case of borrowing code from multiple places – but first try this D64 disk image with any Commodore 64 emulator or a real C64:
The monitor built into the Final Cartridge III is one of the best ones for the C64. Some of its unique features are:
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 “Standard Serial” bus as found on the VIC-20/C64 as the main bus, but also supported by all other Commodore home computers.
The GEOS operating system for the Commodore 64 achieved to replicate much of the GUI of the original Macintosh on a 1 MHz 8 bit CPU with just 64 KB of RAM. The GEOS Demo is a presentation by Berkeley Softworks (BSW), the creators of GEOS, to showcase the features of GEOS and BSW’s applications.
This is the previously unpublished “Commodore 264 Series Preliminary Users Manual”, a prerelease version of the manual of what came to be the Commodore Plus/4.
Here are some hi-res photos of the Commodore 232 and Commodore 264 prototypes. The C-232 and C-264 were two1 of the planned models of the TED series, but neither shipped. The C-264 became the Plus/4, with productivity software preinstalled in ROM, and the low-lost C-232 was replaced by the even lower-cost C16 and C116 models.
I have previously analyzed the ROM images of some third party disk drives for the Commodore 64: The result was that most of them were just using the original binaries with some obfuscation, and some with some added features. This time, let’s look at another drive, the “Technica”, which is a little special in this regard.
I have this pile of broken GEOS disks that were sent in for replacements. In two previous articles (1, 2), I explored the reasons why the disks broke. Now let’s be constructive: Can we reconstruct the original bits by combining the correct parts? This article shows how it is possible with the help of a small tool that combines the good parts of several broken disk images.
I happened to come across 50 original German GEOS 2.0 disks that were broken and sent in for replacement. In the first part, I covered the disks that were broken probably due to user error. Now let’s look at the read errors on the remaining disks. As it turns out, there might be a bug in GEOS that caused the boot disks to break!
An unmodified Commodore 1541 disk drive cannot transfer the raw bits of a whole track to the computer it is attached to: The Commodore Serial Bus is too slow to transmit the data in real time as it arrives from the read head, and the drive only has 2 KB of RAM, which is not enough to buffer the 8 KB of a whole track.