I've looked through manuals and can't come up with something definitive:
what is the difference between the 850 and an 851 (or for that matter 800
vs. 801 or 900 vs. 901)? TIA!
The xx1 models incldue the extra circuitry (monostable and a few gates,
absically) to handle hard sectored disks (and output the correct secotr
and index pulses). xx) models don't
For use with a PC you want soft sectoring anyway. The extra logic on an
xx1 can be disabled (jumpers on the drive PCB) so either will work for you.
-tony