17 Apr
1997
17 Apr
'97
4:32 a.m.
On Thu, 17 Apr 1997, Barry Peterson wrote:
Soft-sector (common IBM-compatible) disks have only
one hole.
(Called the index hole?) Hard-sector disks have multiple holes
which define where the sectors will be. The disks I have, close to 350
of them actually, are 16-sector disks which have a total of 17 holes.
Not at all suitable for IBM-compatible usage but I understand
Commodore 64 and possibly other systems ignore the holes.
The systems best known for ignoring ALL holes in floppies are the
original Apples and their descendants. Woz apparently couldn't afford
a real controller, so he did it all in software. The Apples read the
whole track and determine what's on it from memory. Naturally this
made the Apple disk subsystem the slowest thing possible until the
geniuses at Commodore outdid them by using a serial disk interface.
(And people complained about the TRS-80 cassette system -- well, it's
the only one that had a cassette system reliable enough to put off
upgrading to disk, so people had _time_ to complain.)
--
Ward Griffiths
"Men will never be free until the last king is strangled with the entrails
of the last priest." [Denis Diderot, "Dithyrambe sur la fete de rois"]