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From: leonard@bucket.UUCP
Newsgroups: sci.crypt
Subject: Re: Erasing magnetic media
Message-ID: <590@bucket.UUCP>
Date: Thu, 12-Nov-87 00:35:56 EST
Article-I.D.: bucket.590
Posted: Thu Nov 12 00:35:56 1987
Date-Received: Sat, 14-Nov-87 14:35:48 EST
References: <7566@reed.UUCP> <1175@cup.portal.com>
Reply-To: leonard@bucket.UUCP (Leonard Erickson)
Organization: Rick's Home Grown Unix; Portland, OR
Lines: 22

In article <456@ucdavis.ucdavis.edu> hildum@iris.UUCP (Eric Hildum) writes:
<
<I believe that the Curie point for most commonly used media is 200
<Celsuis - which should be hot enough to destroy the mylar of tapes or
<floppies. As for hard disks, once it is no longer magnetic, you will
<have a hard time writing new data onto it, won't you?
<
<						Eric

I'm not so sure that that is high enough for damage but it is probably
too close. I _do_ know that there is a high speed tape duplication system
that heats the media past the Curie point and then cools it in "contact"
with the media to be duplicated. As the media cools it will _easily_
align its domians with any applied field.

As for hard disk media, the material becomes magnetizable after it is cooled.

-- 
Leonard Erickson		...!tektronix!reed!percival!bucket!leonard
CIS: [70465,203]
"I used to be a hacker. Now I'm a 'microcomputer specialist'.
You know... I'd rather be a hacker."