Path: utzoo!attcan!uunet!mcsun!unido!mpirbn!p554mve
From: p554mve@mpirbn.mpifr-bonn.mpg.de (Michael van Elst)
Newsgroups: comp.sys.amiga
Subject: Re: Reading 1581 disks
Message-ID: <1252@mpirbn.mpifr-bonn.mpg.de>
Date: 27 Sep 90 20:43:01 GMT
References: <2041@lpami.wimsey.bc.ca>
Reply-To: p554mve@mpirbn.UUCP (Michael van Elst)
Organization: Max-Planck-Institut fuer Radioastronomie, Bonn
Lines: 23

In article <2041@lpami.wimsey.bc.ca> lphillips@lpami.wimsey.bc.ca (Larry Phillips) writes:
[on C64 disk]
>If memory serves, there were no track to track red speed changes... only a
>smaller number of sectors per track as you approached the center of the disk.
>This happened in zones. It's been a while though. I could be mistaken. I
>do remember being a little baffled about this when Don Lekei and I were writing
>DiskDoctor (the PET one, not the Amiga one).

The standard 1541 format uses four different speeds. How would you
get fewer sectors on the inner tracks ? You could omit some and leave
a gap. You can also drop the (data transfer) speed that the gap vanishes.
What you get is a more homogenous bit density (measured in flux transitions
per inch) that allows you to reach the upper limits of the bit density
on the outer tracks.
So it's actually not the inner tracks with fewer sectors but the outer
tracks with more sectors :-)

Regards,
-- 
Michael van Elst
UUCP:     universe!local-cluster!milky-way!sol!earth!uunet!unido!mpirbn!p554mve
Internet: p554mve@mpirbn.mpifr-bonn.mpg.de
                                "A potential Snark may lurk in every tree."