> 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).
>
> 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_at_alcor.concordia.ca
--
-tony
ard12_at_eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill
Received on Thu Jun 19 1997 - 12:55:05 BST