[Christian Zietz] wanted to know more about the Atari ST. He found information online from newer Atari machines like the Falcon030 and the Jaguar, but couldn’t find much else. While looking through some archives of old disk images from the Atari headquarters, he found a folder marked “Drawings\4118.” With some detective work and emulation of an old operating system, he was able to recover the schematics for the ST-4118 video shifter ASIC (Application-Specific Integrated Circuit).
Unfortunately, this appeared to be a chip for the unreleased Atari Panther video game console. However, it did show the way to how these older schematics were readable. [Christian] continued searching and found some floppy disk images that were a bit unusual. They didn’t have a proper file system but had been created by a backup program called FastBack for MS-DOS.
Simulation with DOSBox wasn’t good enough for the old versions of FastBack, so that was a dead end. However, there was a version for Windows 95 that would work in VirtualPC. The only problem: It expects 3.5-inch floppy media rater than the older 5.25-inch of the original backups.
[Christian] wrote a program to convert the images over and was then able to restore most of the 27-year-old backup archive. Although one floppy image was missing and there was some corruption, he wound up with hundreds of schematics and timing diagrams dating back to 1986 with multiple versions of important Atari chip designs from that era.
He admits he hasn’t found everything. If you are interested in helping, he has the entire set of archives and some additional information linked in his post. We know that poring over three-decade-old schematics isn’t everyone’s cup of tea, but if you enjoy this sort of thing then his work should give you a thrill.
This is a great example of a growing problem. So much data is locked up in formats and media that we are losing the ability to access. Regardless, we do love the old computers. No matter if it is a $4 Z80 build or reviving the Amiga 1200 from photographs, we are into it.