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From: cfiaime@ihnp4.UUCP (Jeff Williams)
Newsgroups: net.micro
Subject: Re: Erasing Disks
Message-ID: <736@ihnp4.UUCP>
Date: Wed, 13-Mar-85 08:49:43 EST
Article-I.D.: ihnp4.736
Posted: Wed Mar 13 08:49:43 1985
Date-Received: Thu, 14-Mar-85 04:39:58 EST
References: <1960@sdcc6.UUCP>
Organization: AT&T Bell Laboratories
Lines: 24

> I had seen ads advertising a device to erase floppy disks much as a
> tape eraser works on cassettes.  I had heard that this increases the
> life of old disks, much as tape life is extended (or at least the
> usefulness of old tape) by the tape eraser.  The device claimed to
> allow disks to have their lives extended via a "repositioning of the
> magnetic particles on the disk to the pattern they were set at by the
> factory."  This doesn't sound quite kosher.  Can disk life REALLY be
> extended by periodic erasing?

It is funny that you mention this.  Last night I was talking with a DEC
c.e. concerning floppy disks on a PDP 11/23+.  One of the comments that
he made was that if a bulk eraser is used on a floppy for that system,
servo (head) positioning data is lost on the floppy, and the disk is
totally useless.  There is no field program to reformat that part of the
disk, at least according to him.  I have no reason to doubt him.

Of course, we were talking about one specific system, and one type of
drive (the RX02).  These comments may not apply to a 5 1/4 inch drive
on a PC, but do you want to experiment?

					jeff williams
					AT&T Bell Laboratories
					Naperville, Ill.
					ihnp4!cfiaime