5 Jun
2014
5 Jun
'14
7:25 a.m.
On 04/06/14 3:25 PM, Tony Duell wrote:
Pretty sure all the Mac/Lisa 3.5" drives are variable speed as well,
thanks to the IWM? You can certainly hear the RPM changes.
--Toby
I was looking
at it from a conventional viewpoint--with the disk turning
at a constant speed, which is the way most people view them today.
Saying "variable speed spindle" doesn't convey quite the same level of
arcaneness to me.
I think a disk turnign ant differnet speeds to read/write different
tracks is somewhaat more arcane than a changing data rate.
However , the origianl Sirius drives were varaible rate. I don't have
the scheamtic to hand, but IIRC there's a microcontroller (8048?) that
takes in a 4 bit speed value for each drive, takes in the tacho signals
and outputs a cotnrol signall to the motor driver. And yes, you can hear
the speed change ans youformat a disk.
-tony