[Coco] 80 track disk access under RSDOS
flexser at fiu.edu
Wed May 5 12:22:31 EDT 2004
On Wed, 5 May 2004, (John Kowalski) wrote:
> By the way, if you wanted to store a lot of 35-track-readable files onto an
> 80 track disk, you could write a simple program to mark 'used' all granules
> above 68 in the GAT (track 17, sector 2 - each byte represents a granule.)
> Then save up to 68 granules of files onto the disk.
> Then run another program to mark 'free' all granules above 68 in the GAT.
> Now you can keep adding more files to the 80 track disk, while all of the
> previously added files are guaranteed to load on a 35 track system.
> John Kowalski (Sock Master)
You'd also have to knock out the Disk Basic routine that zeroes out the
GAT above 68 grans. This routine was defective in at least Disk Basic
1.0, if I recall, filling those grans above 68 with garbage instead of
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