30 Oct
2001
30 Oct
'01
2:49 p.m.
Yeah ... what I intended the reader to take from this is that since it's
entirely up to the software to determine what, if anything, is done with
information gained, or not, from the index/sector holes in a diskette, a system
that can ignore them as the Apple does, or one that looks only when they're
nominally supposed to occur, doesn't care whether the media is intended to be
used soft or hard sectored.
8" drives with the "hard-sector-option" installed have jumpers to open a
window
in time, typically with one-shots, to allow the detection or suppression of
sector holes into 8, 16, or 32 sectors per revolution, even though the media has
32 sector holes and a single index hole, all on one track. That's the same
strategy applied in hardware. If you don't really care about where the
information is located on the medium, it doesn't matter whether you open a
window at all, since you're not going to look for it. Instead, you can paint
your own window wherever you like, and use that.
Dick
----- Original Message -----
From: "Sellam Ismail" <foo(a)siconic.com>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, October 30, 2001 9:23 PM
Subject: Re: hard-sector 5 1/4 disk
On Tue, 30 Oct 2001, Richard Erlacher wrote:
It's conceivable that the software that the
Apple][ used didn't look
for an index pulse until, nominally, the "right" time, at which point
it waited for it, then proceeded, in which case the extra holes in the
index track (not a magnetic track) would have no impact.
The Apple Disk ][ simply has no mechanism for even detecting the index
hole, so this is not even moot.
I'm having trouble parsing your paragraph so you may well be saying the
same thing.
The format was, nevertheless, soft-sectored,
thereby allowing a smooth
transition from 13 sectors to 16 sectors, without a major redesign.
Yes.
Sellam Ismail Vintage Computer Festival
------------------------------------------------------------------------------
International Man of Intrigue and Danger http://www.vintage.org