This allowed for the directory volume to be rebuilt, one byte at a time.
This required figuring out the offsets and sizes of the files, assisted by knowing what was likely on the disk, and having some bits and pieces of the original volume listing still intact. This required diving into the technical reference manual for ProDOS and its filesystem to figure out how to reconstruct the directory layout. It also confirmed that the sector containing the directory listing was shot. This data could then be analyzed sector by sector, with the bad sectors and the cause for ProDOS flaking out with its reading attempts here marked in red.Ĭhecking the data recovered so far confirmed that it was a ProDOS disk. The gist of the story is that the floppy disk’s surface could still be scanned with help from the aptly named Applesauce Floppy Drive Controller, which got the following visualization of the magnetic patterns on the disk surface:
Applesauce visualization of the patterns on the corrupted disk, with soft-sectoring spiral arms. Not deterred, he set about to recover the data, as documented in this Twitter thread. Fast-forward thirty years to today and found to his dismay that ProDOS could no longer read the floppy, giving an I/O error. The BASIC source code and images for the game were stored on a single ProDOS formatted, soft-sectored 5.25″ floppy disk. Back in 1990 wrote – while in elementary school – a dog racing game called Wonderland 2.
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