19 Jan
2006
19 Jan
'06
3:23 p.m.
At 12:01 PM 1/19/2006 -0600, you wrote:
Subject: deformatting floppies
I would have thought it best to take a magnet to a hd
disk before popping in a 720k drive to be formatted,
but it seems to not have any (or much) effect. Even
using a chunky rare earth magnet! Can someone explain?
NOT a good idea: using a PERMANENT magnet. Could leave permanent magnetism
on the HEADS. I have been successful using a "bulk tape eraser" from Radio
Shack.. The kind useable on tape cassettes would be OK.. Move the disk
around a few times in contact with the eraser, then turn at right angles
and SLOWLY draw it away. Think slowly decreasing sine wave. This should
demagnetize the disk well, and MOST disks that give "Bad Media or Track
Zero" can be formatted.
Regards, Terry King ...On The Mediterranean in Carthage, Tunisia
terry at terryking.us
20 Jan
20 Jan
10:44 a.m.
On Thursday 19 January 2006 15:23, Terry King wrote:
At 12:01 PM 1/19/2006 -0600, you wrote:
<snip>
One should probably point out that trying to format HD 3.5" media (aka
1.44MB or 2.0MB) in a 720kB drive won't work reliably, no matter how
well you degauss the media. The problem lies in the coercivity of the
media (and has been discussed on this list several times in the past
couple years I've been here).
Pat
--
Purdue University ITAP/RCS --- http://www.itap.purdue.edu/rcs/
The Computer Refuge --- http://computer-refuge.org
Subject: deformatting floppies
I would have thought it best to take a magnet to a hd
disk before popping in a 720k drive to be formatted,
but it seems to not have any (or much) effect. Even
using a chunky rare earth magnet! Can someone explain?
11:31 a.m.
Patrick Finnegan wrote:
On Thursday 19 January 2006 15:23, Terry King wrote:
Although one thing I've found with many years experience with PS/2's is
that 1.44MB drives in PS/2's reliably can treat 720kB floppies as 1.44MB
floppies without any trouble whatsoever. I mean, without covering the
hole or anything like that.
Peace... Sridhar
At 12:01 PM 1/19/2006 -0600, you wrote:
<snip>
One should probably point out that trying to format HD 3.5" media (aka
1.44MB or 2.0MB) in a 720kB drive won't work reliably, no matter how
well you degauss the media. The problem lies in the coercivity of the
media (and has been discussed on this list several times in the past
couple years I've been here). Subject: deformatting floppies
I would have thought it best to take a magnet to a hd
disk before popping in a 720k drive to be formatted,
but it seems to not have any (or much) effect. Even
using a chunky rare earth magnet! Can someone explain?
1:19 p.m.
On 1/20/2006 at 11:31 AM Sridhar Ayengar wrote:
Although one thing I've found with many years
experience with PS/2's is
that 1.44MB drives in PS/2's reliably can treat 720kB floppies as 1.44MB
floppies without any trouble whatsoever. I mean, without covering the
hole or anything like that.
Indeed. While there is ostensibly a difference in coercivity in the media,
it's not as large as it is between 1.2MB and 360K media. I still might
even have a diskette punch to add the hole to 720K diskettes kicking
around. Should anyone be curious, I think I still have media
characteristics sent to me by 3M. Since the PS/2 used drives that were
"blind" to the added hole, swapping DS2D media for DSHD was very common.
We still see this a lot from customers with machine tools and lab equipment
requiring 720K media--since they're using 720K drives without the media
sensor, they routinely use DSHD media without bad effects. When we read
the disks, we either use a 720K drive or just cover over the hole
temporarily.
Cheers,
Chuck
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