19 Jun
1997
19 Jun
'97
10:11 p.m.
On Thu, 19 Jun 1997, A.R. Duell wrote:
Interesting. I had read that those drives were variable speed, but from a
much less reliable source than service manuals. Thanks for the
clarification!
That true regeading the mass of the flywheel motor on floppy drives
is pretty heavy. Hey, what about the Mac that did still use 4 speed
disk drive, you can hear the differences in speeds made clearly by
formatting a disk.
Jason D.
Uh, I beg
to differ about the Victor 9000 being the first computer to use
variable speed disk drives, as my CBM 2040 dual drive unit from 1979 does
this.
No it doesn't (or at least the 8050 doesn't, and nor does the 1541 - I
have service manuals for both of them)
The disk turns at a constant speed. What changes is the speed of the data
clock. The bits are sent faster for the outside tracks, so it can fit more
sectors on said tracks. I never really saw the point of variable-speed
drives. Changing the data
clock is a lot easier, and probably faster (getting the spindle
up-to-speed and locked at that speed takes considerable time).
Yup, you're right.
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
Doug Spence
ds_spenc(a)alcor.concordia.ca