4 Oct
1999
4 Oct
'99
4:53 a.m.
QD is a
misnomer, it really means DSDD 80-track, and the figure of 720K
relates to 9 sectors per track, 512 bytes per sector.
QD was 96tpi TWO SIDED. There were two formats, 720k and 780k. There were three basic soft sector medias, 35track
(small window for
head), 40 track (larger window) and the 600o 1.2mb. Obviously there were
flavors of single and two side good media. Most large window was two
sides good and worked in everything save for the odd 1.2mb drives.
Eh? What about QD? Which was that? It wasn't 35 or 40 track, but 77 or 80.
Given the Wabash label quoted above, can you confirm absolutely that the number
of tracks was a variation in head window?
Philip.
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4 Oct
4 Oct
6:34 a.m.
Come on, Allison, read the message before hitting the
shift key. He said two
Shift in pine is next page.
sided (embedded in the word "DSDD"). Some
(Wabash?) QD disks I saw were
labelled "96/100 tpi 77/80 track" or words to that effect.
QD was used to imply a lot of mostly marketing hype. In general it was
simple twosided media that was cetrified for both surfaces good. What
the floppy controller did to put stuff on it was an entirely different
matter.
Eh? What about QD? Which was that? It wasn't 35
or 40 track, but 77 or 80.
Given the Wabash label quoted above, can you confirm absolutely that the number
of tracks was a variation in head window?
The window size was older media when did drives didn't ahve more than 35
tracks. LAter drives that had 40 tracks needed a longer window or the
head would hit it. Had nothing to do with QD as that was more tracks
fitted to the same recoring area as 40 track (the 100 tpi were very
close).
Part of all the confusion is there is a limited set of medias and a
broader set of drives (35tr, 40tr, 96tr, one sided and two sided) and
then there were the FD controllers and their capabilities plus what the
software could drive them too.
Now if we take one media, standard 300o 5.25 twosided 96/100tpi certifed
we are now talking about litterally hundreds of formats most of which are
incompatable not by any reason of media.
Allison
9:50 a.m.
Allison wrote:
The window size was older media when did drives
didn't ahve more than 35
tracks. LAter drives that had 40 tracks needed a longer window or the
head would hit it. Had nothing to do with QD as that was more tracks
fitted to the same recoring area as 40 track (the 100 tpi were very
close).
I'm skeptical; in all the time I've bought 5.25 inch floppy diskettes
(since 1976), I've NEVER seen one that had a shorter head window.
I'd be willing to pay $20 for such a diskette for my collection.
I've seen plenty of DRIVES that couldn't step past tracks 34-36, but
that was a mechanical limitation of the drive.
11:16 a.m.
I'm skeptical; in all the time I've bought 5.25 inch floppy diskettes
(since 1976), I've NEVER seen one that had a shorter head window. I'd
be willing to pay $20 for such a diskette for my collection.
I have em. Both 10 sector NS* format (no even for $20 I dont give them
up) and also some of my TI99/4a likely others that I'd have bought around
78-79. Drive me nuts when I went to the 40 track SA400L. Kept getting
errors beyond track 36! Turns out the media has a smaller window.
I've seen plenty of DRIVES that couldn't step
past tracks 34-36, but
that was a mechanical limitation of the drive.
I know, I still have the SA400 supplied with my MDS-A, a 35 track model
and a lot of media from back then for the ICOM FDOS controller.
Allison
12:16 p.m.
Allison wrote about 5.25 inch diskettes with small (35-track) head windows:
I have em. Both 10 sector NS* format (no even for $20
I dont give them
up) and also some of my TI99/4a likely others that I'd have bought around
Wow! What brand of diskettes were they? All the NS diskettes I've seen
have the standard windows, but I think they were just 3M and Verbatim
diskettes.
Cheers,
Eric
8:07 p.m.
On 4 Oct 1999, Eric Smith wrote:
Allison wrote about 5.25 inch diskettes with small
(35-track) head windows:
I have a couple (and perhaps more) Verbatim 10 sector diskettes for N*
that have the short window.
- don
I have em. Both 10 sector NS* format (no even
for $20 I dont give them
up) and also some of my TI99/4a likely others that I'd have bought around
Wow! What brand of diskettes were they? All the NS diskettes I've seen
have the standard windows, but I think they were just 3M and Verbatim
diskettes.
9031
days inactive
9032
days old
5 comments
4 participants
participants (4)
-
allisonp＠world.std.com -
donm＠cts.com -
eric＠brouhaha.com -
Philip.Belben＠powertech.co.uk