Tony wrote
I am wondering how on earth you can make a disk
controller (note, not the
OS driver software, the physical controller) that works correctly with a
9-sector-per-track format, but fails with the 8 sector-per-track version,
all other parameters being the same. Because that's the only difference
between the 320K and 360K MS-DOS formats.
Only if you were to make an "intelligent"* controller that was designed to
work as a sort of co-processor with less interaction with the main system.
OK... I'll bet that no normal PC motherboard uses such a controller,
though...
I have found PC disk controllers that can't handle 360K disks. When used
in 1.2M (360rpm drives), such disks have an effective 300kbps data rate,
which the (broken-as-designed) controller didn't handle. I complained
about this, only to be told that 'nobody uses 360K disks any more'.
Hmmm... It claimed to be 'IBM compatible', and the IBM controller
certainly handles 360K disks...
-tony