20 Jun
1997
20 Jun
'97
12:18 a.m.
On Thu, 19 Jun 1997, Roger Merchberger wrote:
Not the Amiga, it uses a constant rotation speed and data rate. The Amiga
gets the "extra" space on the disk by simply not using sector headers.
When a sector is needed, the entire track it lives on is read into a
buffer, and when a modification is made the entire track is written back
out.
The lack of sector headers allows the Amiga to write 11 sectors per track,
instead of 9 as with the PC. (In practice, though, I can safely get 12
sectors per track, and I understand it's possible to go higher.)
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).
<snip>
-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.
Doug Spence
ds_spenc(a)alcor.concordia.ca