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From: farren@gethen.UUCP (Michael J. Farren)
Newsgroups: comp.sys.ibm.pc
Subject: Re: new floppy format proposal
Message-ID: <300@gethen.UUCP>
Date: Fri, 6-Nov-87 15:46:03 EST
Article-I.D.: gethen.300
Posted: Fri Nov  6 15:46:03 1987
Date-Received: Mon, 9-Nov-87 06:28:33 EST
References: <4289@cit-vax.Caltech.Edu> <1155@cup.portal.com>
Reply-To: farren@gethen.UUCP (Michael J. Farren)
Organization: Sci-Fido - Unix in Oakland
Lines: 23
Keywords: high-density floppy

In article <6343@sunybcs.UUCP> ugfailau@joey.UUCP (Fai Lau) writes:
>	The difference in the coating is the size of the magnetic
>particles and their density. Otherwise the coatings are pretty
>much the same for normal disk and high-dens disk. They might
>also change the coating for the particles (not the disk coating
>which *contains* the particle) for the difference in
>roatation speed, if there is any. And off cause, you can
>always write a high density disk with a normal drive..

No you can't.  Not reliably.  Regardless of whether or not the coating
on a HD diskette is physically similar to the coating on a normal
drive, the media has a higher coercivity, thus requiring a different
head assembly, one which can produce the levels of flux required to
change the state of the media.  Normal drives don't have it.

My intuition is that the coatings of a normal diskette and a HD diskette
are, in fact, quite different.  I don't have proof of this, but they
look different to my eye.

-- 
----------------
Michael J. Farren      "... if the church put in half the time on covetousness
unisoft!gethen!farren   that it does on lust, this would be a better world ..."
gethen!farren@lll-winken.arpa             Garrison Keillor, "Lake Wobegon Day!po