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From: ma168x@sdcc3.ucsd.EDU (John Wavrik)
Newsgroups: net.micro.pc
Subject: 1.2meg <-> 360k
Message-ID: <3667@sdcc3.ucsd.EDU>
Date: Thu, 30-Oct-86 02:08:41 EST
Article-I.D.: sdcc3.3667
Posted: Thu Oct 30 02:08:41 1986
Date-Received: Thu, 30-Oct-86 23:22:44 EST
Organization: University of California, San Diego
Lines: 26
Keywords: AT disk drives


Several times in my life I have been in the position of listening to a
lengthy explanation of why it is impossible to do something I've already
done.  I still don't know how to react.
   According to the explanation recently given by John Plocher, it should
be impossible to do the following:  write a track on a 360k drive, rewrite it
with a 1.2 meg, get a good read on the original 360.  If one is to believe
the pictures, the 1.2 will record on only a small part of the 360k track --
so an attempt to read will produce a garbled mixture of new information from
the 1.2 and old from the original 360.  I have no difficulty following the
theory!
  When I recently acquired a Tandy 3000 someone suggested I get one of each
kind of drive.  They gave essentially the same warning about track width.
I did not follow the advice -- I got two 1.2 meg drives even though I need to
exchange data with an older machine using 360k.  I found it is fairly easy to
avoid having both machines write to the same disk -- but the recent postings

aroused my curiosity.  I ran some tests using Forth (so I could be sure that the
same tracks were being used by both machines).  I could not produce any problems
no matter what.
    I think that anyone should use caution when writing to one disk with two
computers -- there is always the possibility that the heads on one machine are
mis-aligned.  I can only report that there must be something wrong with a
theory whose predictions are not supported by experiment.
						     --J Wavrik
							UCSD