50Hz vs 60Hz fixed drive speed ?

From: Paul Koning <pkoning_at_equallogic.com>
Date: Tue Feb 17 16:04:39 2004

>>>>> "Tom" == Tom Uban <uban_at_ubanproductions.com> writes:

 Tom> Well if you are talking about modern hard drives, then you are
 Tom> of course correct. But then that wouldn't be on topic for this
 Tom> list. My question revolves around the old vintage hard drives
 Tom> with fixed platters driven by A/C motors.

One data point: at least some of the DEC head-per-track fixed disks --
RS64/RC11 and RF11 -- were constructed with spindles just like modern
hard drives, the motor and platter bearing assembly all a single
unit. In other words, there aren't any pulleys or the like in that
setup. But the motors were AC motors, so in that case you'd
definitely end up with a rotation speed dependent on the power line
frequency.

I don't know if the 16% difference was big enough to require tweaks to
the drive electronics -- the PLL in the data recovery circuit,
specifically. Perhaps so.

       paul
Received on Tue Feb 17 2004 - 16:04:39 GMT