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From: md@ncsu.UUCP ( )
Newsgroups: net.micro.apple
Subject: Re: Re: Apple disk speed -- more info
Message-ID: <2634@ncsu.UUCP>
Date: Mon, 25-Jun-84 17:22:27 EDT
Article-I.D.: ncsu.2634
Posted: Mon Jun 25 17:22:27 1984
Date-Received: Tue, 26-Jun-84 06:29:07 EDT
References: <1483@decwrl.UUCP>
Organization: N.C. State University, Raleigh
Lines: 23


Apple DOS also uses a little bit of intelligence in accessing the sectors
on a disk.  Using a sector interleaving scheme in software is what allows
both Apple and third party Dos to alter the sector interleaving pattern.
I admit that Apple's might not be the best but this is what it is.

	physical sector		logical sector
	   0			   0
	   1			   7
	   2			   14
	   3			   6
	   4			   13

   etc.

Apple DOS is slow for several reasons, but SAVE, and BSAVE times can be
improved by removing the VERIFY routine that is executed after each 
SAVE or BSAVE.  Replace those JSRs with NOPs.  This is one method that those
third party DOSes use to improve their speed.

			Mike Davis