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From: shack@cs.arizona.edu (David Shackelford)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: Disk from model 30 wont be read in other machines
Message-ID: <570@caslon.cs.arizona.edu>
Date: 30 Nov 90 16:39:04 GMT
References: <1990Nov29.060240.11369@ncsuvx.ncsu.edu> <109480@convex.convex.com>
Distribution: comp
Organization: U of Arizona CS Dept, Tucson
Lines: 40

In article <109480@convex.convex.com> macphee@convex.COM (Scott C. Mac Phee) writes:
>In article <1990Nov29.060240.11369@ncsuvx.ncsu.edu> jumper@hobbes.ncsu.edu (Michael Lanham) writes:
>>I used diskcopy to copy the originals
>>to the backups alos using the model 30 as the copy platform.
>>
>>
>> blah blah..
>>
>>WHY??????  I tried to use a friends model 50 (IBM PS/2) and his machine
>>would not read the second disk either.  All three machines read the INSTALL
>>disk but only my model 30 will read the other needed diskettes.
>>
>>Help would be deeply appreciated
>>
>Wild Guess, here.  If the disk is a double-density disk, your low-density
>3 1/2 formatted it low density.  The high density drive looks at the
>physical mark (a hole thru the corner) of the diskette and says " Hey,
>this is a high-density diskette!  I can't read it!".
>

This could be the problem, but not likely.  Also, there is a technical
mistake in this posting -- the HD diskette has an extra hole, the DD
diskette does not.  This means that on some computers, if a DD disk was
formatted at HD, the drive sees the lack of a hole and assumes it can
only be formatted DD.  It fails to read the formatting at 720K and 
returns an error.

The reason I'm not sure this is the actual problem, is that many (possibly
all) PS/2 50's have the type of drive that doesn't care if that hole is
present or not.  Also, the mismatch problem only occurs if the diskette
is formatted at 1.44M, so if the original diskette that was DISKCOPY'd
was formatted at 720K it shouldn't cause this problem.

If the original disk was 720K, I recommend trying the copy again by using
FORMAT (or other suitable replacement) first, then copying using some
other means than DISKCOPY and see if that works.

Hope this is some help,

Dave    | shack@cs.arizona.edu