List of the EXDOS floppy driver capatibilities:
Let me comment this for SymbOS:
[OK] can handle four drives (A,B,C,D)
[OK] drive can be a 40 or 80 tracks, single or double sided, any combination of these
[OK] drive types can be mixed in any combination
[OK] 40 tracks disks can be used in 80 tracks drive with double stepping
[OK] at non compatibility situation (80 track disk in 40 track drive or a double sided disk in single sided drive) error reported
If it doesn't require a different programming of the WD, this should work, too:
[OK] handle 8,9,10,11 sectors/track disks
[OK] plus tracks don't problem (I have a 90 tracks drives
), most commonly used disk format 84x2x10=840K
This should work, too, but has to be tested:
[OK] don't use Drive Ready signal, then no problem with modern drives
[OK] at default don't use Disck Change signal, then also no problem with modern drives
This isn't supported:
[N/A] disk compatibility checked, double stepping automaticaly switch on or off
I have no idea about this:
[??] works reliable at different speed machines (from 4 to 10Mhz tested yet)
[??] exist a Turbo EXDOS hack, where WD overclocked to 10Mhz then 13 sectors/track can be stored with normal DD disks and drives, it is can be work both WD1770 and 1772
[??] more Turbo
, 13.333Mhz for 1.2M drives (300rpm mode) with HD disks, and 16Mhz for 1.44M drives with HD disk. With 1.44 drive can be up to 22 sectors/disk. Exist a different configuration where 1.2M drives run at 360rpm then 9.6Mhz used for handle DD disks, and 16MHz for HD.
Another:
EXDOS card built with WD1770 or WD1772, at 1770 the step rate 0 are the fastest, 6ms. With 1772 the step rate 3 will be faster, 3ms. About 99% of the drives in the world can be used with 3ms, then faster and quiet. (The fastest with 1772 the step rate 2 which are 2ms.) EXDOS have a variable where can selecet the step rate. [...] I think need a Setup option or Configuration windows or something for select step rates and enable/select turbo modes.
I wonder how to support the Turbo modes, what different WD-programming they require...