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From: rb@mtuxn.UUCP (R.BOTWIN)
Newsgroups: net.micro.atari
Subject: Re: Single to double density switching
Message-ID: <691@mtuxn.UUCP>
Date: Wed, 12-Feb-86 11:20:41 EST
Article-I.D.: mtuxn.691
Posted: Wed Feb 12 11:20:41 1986
Date-Received: Fri, 14-Feb-86 01:17:25 EST
References: <328@sask.UUCP> <8602101243.AA03314@ucbvax.berkeley.edu>
Reply-To: rb@mtuxn.UUCP (01161-R.BOTWIN)
Organization: AT&T Information Systems, Holmdel NJ
Lines: 19
Summary: 



[]
David mentions reading sector 1 to switch densities, but I don't believe
that is what was asked, or will in fact help.

In fact, to insure compatible booting, the first three sectors are
always 128 bytes, even if 18 X 256 DD formatting is used on the
remainder of the disk.

Most switchable drives use additional commands (M, N, O) to switch
density according to a table passed in the call.  These are documented
by manufacturers using the system developed by PERCOM, and copied
by AMDEK, ASTRA, TRAK, INDUS, etc. (even ATARI)....

If you need the table layout, I can probably dig it up....

	Rob Botwin, N2FC
    .....{utah-cs|seismo|decvax}!harpo!eagle!houxm!mtuxo!mtuxn!rb
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