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From: clt@pur-phy.UUCP (Carrick Talmadge)
Newsgroups: net.micro.apple,net.micro,net.rumor
Subject: Re: Apple drives may have more storage?
Message-ID: <1337@pur-phy.UUCP>
Date: Tue, 22-May-84 16:20:33 EDT
Article-I.D.: pur-phy.1337
Posted: Tue May 22 16:20:33 1984
Date-Received: Sat, 26-May-84 10:03:43 EDT
References: <1497@sdccs6.UUCP>
Organization: Purdue University Physics Dept.
Lines: 18


	The way I understand it the Apple ][ analog board does use the
MFM recording scheme.  Also as Dave Seaman reported, the problem is in
the Tandem drive itself.  It can half-track so as to give an appearance
of 80 track drives, but, as I understand it, there are two reasons why
this can't be utilitized to double the amount of info stored on a disk.
First, the width of the track written to disk by the magnetic head is
too wide to allow adjacent half tracks to be written without overlap, and
secondly, even if the magnetic head could produce a sufficiently "thin"
recording track, the head positioning mechanism is not precise enough to
take advantage of it.   Some computer manufacturers such as Commodore get
around this by writing more than 16 sectors to disk on the outer tracks,
but this leads to an anoumously high diskette failure rate...

				Carrick Talmadge

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