The Ultimate Commodore 1541 Disk Drive Talk [video]
This is the video recording of “The Ultimate Commodore 1541 Disk Drive Talk” at VCF West 2021. As always, if you think it’s too fast, try watching it at 0.75x speed!
Floppy Disks
[Announcement] The Ultimate Commodore 1541 Disk Drive Talk @ VCFW 2021
After
Ankündigung: Vortrag “Diskettenlaufwerke am Beispiel der Commodore 1541” am VCFB 2020
This post is about an upcoming talk in German.
Inside geoWrite – 5: Copy Protection
In the series about the internals of the geoWrite WYSIWYG text editor for the C64, this article discusses the geoWrite copy protection.
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.
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:
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.
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.
Converting a Commodore 1541 or 1570 Drive into a 1551
The 1551 is the weird outlier in the family of Commodore disk drives: It is the only drive using the “TCBM” bus instead of Serial or IEEE-488. And what’s even weirder? 1541 and 1570 drives converted into 1551s!
More Original Commodore Source Code
There have been a few new interesting additions to the Commodore Source Code repository, including:
Commodore Peripheral Bus: Part 5: TCBM
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 “TCBM” bus as found on the TED series computers: the C16, C116 and the Plus/4.
Blue Chip BCD/5.25 Disk Drive
After previously dissecting the firmware of alternate C64 disk drives, let’s now look at the hardware of one: This is the Blue Chip BCD/5.25.
Recovering Files from Broken Amiga OFS Disks
extract-adf is a tool for recovering files from broken Amiga OFS filesystem images. It can reconstruct directory hierarchies even for files that don’t have directory entries.
The Commodore IEEE-488 Cartridge for C64
Commodore 64 disk drives were usually connected through the slow serial bus. This article shows some hi-res photos of the Commodore “IEEE-488 cartridge”, which made the faster PET drives available for the C64.
Commodore Peripheral Bus: Part 4: Standard Serial
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 Commodore 8250 Dual Drive Floppy Disk
The Commodore 8250 was the high-end 5.25″ disk system for the Commodore PET, with two drives that could each fit 1 MB (4133 blocks free) on a standard disk. Here are some high-res pictures.
Third Party Disk Drives for the C64: The “Technica”
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.
Reconstructing the GEOS 2.0 (de) Master Images from a Pile of Broken Disks
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.
A GEOS Speed Zone Bug? (Why Do C64 GEOS Boot Disks Break, Part 2)
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!