On Jan 21, 15:15, Don Maslin wrote:
> Subject: Re: Reiability of wrong media (was: is out of 5-1/4" diskettes
> On Thu, 21 Jan 1999, Tony Duell wrote:
> > Don't forget that '720K' 5.25" disks also exist, although they're not
> > common on IBM PCs. By that I mean 80 track, double density, double
sided,
> > 300 oersted coercivity. Most of those do not have the reinforcing ring
IIRC.
And they're pretty common on non-MSDOS systems. I far more 80-track DS
drives than 40-track of any flavour.
> > > 720K 5.25" v 360K 5.25": again, an issue of testing/certification,
> > > similar to SS v DS. At least for a while, they were manufactured the
same,
> > > but were tested/certified for 48tpi or 96 tpi.
> >
> > I have had very little success in formatting 48tpi disks in 96tpi
drives.
> > As I mentioned earlier, this includes name-brands like 3M..
>
> Interesting! I have never had a problem using even generic 48tpi disks
> at 96tpi.
> - don
Nor have I, usually. I tend to treat all double-density 5.25" disks the
same. Some of the old ones I have were converted to be "flippy" 40-track,
and some time ago I found one such without a label. Not knowing whether it
really had been formatted flipped, I tried it out, using the
by-now-standard 80-track DS drive and a two-step circuit, and found it had.
"OK, so that's a flippy", I said to myself. A little later, I re-read the
catalogue -- and got a different listing! I had inadvertantly catalogued
side two, with the disk right-side-up -- and realised that the tracks must
not line up, so side two had two sets of data, going in opposite rotations,
with the tracks interleaved!
So I have a three-sided 40 track disk :-)
> > > 3", 3.25": Many newbies will get sloppy in reference to 3.5"
diskettes,
> > > without realizing that there actually were 3" and 3.25" diskettes.
3"
> > > were used by Amstradt, some non-US Canon?, and Amdek add-on drives
for Coco
There are also 2.5" disks, though the only ones I've seen were made by TDK
for an early digital camera. Anyone remember the make? Canon?
--
Pete Peter Turnbull
Dept. of Computer Science
University of York
Received on Thu Jan 21 1999 - 18:27:04 GMT