19 Jun
1997
19 Jun
'97
2:33 a.m.
Due to massive amounts of caffeine & sleep deprivation, A.R. Duell said:
[snip]
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).
That's how it gets 21 sectors on tracks 1 to 17, 20 sectors on tracks 18
to 24, 18 sectors on tracks 24 to 30, and 17 sectors on tracks 31 to 35.
AFAIK, all PET-era CBM drives do this, and the 1540 and 1541 drives do as
well.
> Doug Spence
> ds_spenc(a)alcor.concordia.ca -tony
ard12(a)eng.cam.ac.uk
Righto, Tony! There are programs that you can get for IBM PC's that do this
and you can store 1.8Megs on a 1.44Meg drive!
(Didn't the Apple and Amiga do this with there 800K and 880K drives,
respectively?)
See Ya,
Roger "Merch" Merchberger
--
Roger Merchberger | If at first you don't succeed,
Programmer, NorthernWay | nuclear warhead disarmament should
zmerch(a)northernway.net | *not* be your first career choice.