Fun with degaussers

From: Don Maslin <donm_at_cts.com>
Date: Sun May 2 17:46:37 1999

On Sun, 2 May 1999, Tony Duell wrote:

> > demagnetized. At the time it was explained that the erase heads write a
> > narrower path than the read heads scan so if the track has been magnetized
> > on the outside it can interfere with the reading and writing of a block.
>
> On all drives, the erase head is _wider_ than the R/W head. That's a
> simplification, as actually the R/W head erases the middle of the track,
> but what matters is that the drive erases a wider track than it reads or
> writes.
>
> It has to. However carefully you make and align a drive there will be
> _some_ positioning errors. And if you write a narrow track than you read,
> you'll end up _always_ reading a mixture of what you've just written and
> what was there before.
>
> -tony
>
 
Which is, of course, a major cause of problems in reading a 360k disk that
has been over written as a 360k but in a 1.2mb drive.

                                                 - don
Received on Sun May 02 1999 - 17:46:37 BST