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From: mlinar@eve.usc.edu (Mitch Mlinar)
Newsgroups: comp.os.cpm
Subject: Re: Kaypro DSDD 5.25" floppy parameters
Message-ID: <22926@usc.edu>
Date: 17 Feb 90 03:26:59 GMT
References: <2756@lll-lcc.UUCP> <11425@xanth.cs.odu.edu> <1647@mipos3.intel.com>
Sender: news@usc.edu
Reply-To: mlinar@eve.usc.edu (Mitch Mlinar)
Organization: University of Southern California, Los Angeles, CA
Lines: 14

In article <1647@mipos3.intel.com> dbraun@cadev5.UUCP (Doug Braun ~) writes:
>
>How is it that this format has 10 sectors per track, while IBM PCs
>have only 9 (and the old ones could only get 8 in)?
>

This is possible since a track on disk has lots of stuff around it for
synchronization, etc.  The actual number of bytes per track is fixed and
dependent upon the method and disk size (FM/MFM, SD/DD).

Kaypro "shortchanged" the synchronization header and intermediate headers so
that an extra sector could be squeezed into it.  Nine is possible even
using the manufacturers recommended track format;  IBM used eight originally
because it simplified the BIOS logical to physical sector xlation.