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Path: utzoo!linus!decvax!ittvax!dcdwest!sdcsvax!sdccsu3!brian
From: brian@sdccsu3.UUCP
Newsgroups: net.micro
Subject: Re: ss vice ds disks
Message-ID: <1327@sdccsu3.UUCP>
Date: Sun, 27-Nov-83 15:47:17 EST
Article-I.D.: sdccsu3.1327
Posted: Sun Nov 27 15:47:17 1983
Date-Received: Mon, 28-Nov-83 22:57:29 EST
References: <13926@sri-arpa.UUCP>
Organization: UCSD beer & pizza society
Lines: 14

The reason the index hole is in a different place for SS and DS 8" disks
is so that the drive hardware can report to the controller whether there
is a single sided or double sided disk in the drive.  Since most if not
all of the popular 8" computers retain compatability with IBM 3740
format, this can assist the disk controller software in making a more
intelligent decision.  Some cp/m bios don't even ask what kind of a disk
is in the drive - the make the proper settings based on an identity
sector and the single/double hardware indication (Jade DD is an
example of this).  Sure is convenient!

-- 
	-Brian Kantor, UC San Diego 
	{decvax,ucbvax} !sdcsvax!sdccsu3!brian
	Kantor@Nosc