9 Oct
2007
9 Oct
'07
12:05 a.m.
Industry standard floppy drives (TM100, etc.) have a
write-protect as part
of the drive.
Yep. Even modern PC drives have that I think (certianly all the ones I've
tested do). FWIW, when I do a drive alighment, I put the drive on the
exerciser and try to write a test pattern to a write-protected scratch
disk. If the drive writes it, the alignment disk goes nowhere near that
drive until I've fixed the problem.
The very first time that I dealt with a malfunctioning
Apple][, I
destroyed three boot disks before I realized that that controller and
those drives could wipe out disks even when write-protected.
Just looked at the schemaitcs, and it seems the drive _does_ have
hardware write protect. The WP switch disables a 3-state buffer in the Wr
Req line (everybody else callse it WriteGate) which should stop the drive
from writing. Maybe early versions didn't have that
circuit.
-tony