Are you
suggesting that a platter, weighting several kilograms, spinning
at something like 3600 rpm, suddenly can change spin direction at a
millisecond notice?
This would be ummm interesting if you could make it happen... :-)
Millisecond notice? I'll go you one better. Quantum Mechanics tells us that
the platter is simultaneously spinning both forward AND backward, and
motionless, until YOU had to go and open up the cover and make it assume a
given state ;)
Jay