21 Jan
1999
21 Jan
'99
3:58 p.m.
On Fri, 22 Jan 1999, Pete Turnbull wrote:
On Jan 21, 15:15, Don Maslin wrote:
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!
If you wanted to press your luck, you should be able to expand it to four!
- don
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 So I have a three-sided 40 track disk :-)
donm(a)cts.com
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Don Maslin - Keeper of the Dina-SIG CP/M System Disk Archives
Chairman, Dina-SIG of the San Diego Computer Society
Clinging tenaciously to the trailing edge of technology.
Sysop - Elephant's Graveyard (CP/M) Z-Node 9 - 619-454-8412
*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*
see old system support at http://www.psyber.com/~tcj
visit the "Unofficial" CP/M Web site at http://devili.iki.fi/cpm
with Mirror at http://www.mathcs.emory.edu/~cfs/cpm
> > 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