Re: Macs and GS disks

[CUTjefbla@bconnex.net (Jeff Blakeney)]

On Tue, 20 Feb 2001 10:19:01 -0600, Roy and/or Janet Miller
<millers@inetnebr.com> wrote:

>Both disks are 3M 3.5, DS 135 TPI, and neither have the high density hole.
>Strange, isn't it?

Very strange.

Another thought occurs to me.  Maybe it has to do with what drive
formatted and wrote to the disks or maybe it has to do with how long
the disks have been formatted.

What I'm getting at is maybe the magnetic fields are weaker on the
disk that doesn't work than on the disk that does work or that the
non-working disk was created on a drive that had the write head out of
alignment.  Weak magnetic fields can be caused by age or by weak write
heads in a particular drive or the drive head being too far from the
disk when it wrote to it.  Alignment problems can be caused by age,
heat cycling, physical abuse et al.  However, alignment problems in
3.5" drives is fairly rare.

If you'd like to test either of these theories, format a new floppy on
your IIgs and then try reading it on the Mac.  If that works then take
that disk back to the IIgs and copy the contents of the disk that
didn't work onto that newly formatted disk.  You can either drag all
the files over to do a file copy or drag the non-working disk icon
onto the new disk icon to do a volume copy.  Take that new disk to the
Mac and see if it can read it now.

If it can read the newly created disk then you problem is probably due
to the magnetic fields on the non-working disk being too low or the
alignment of the tracks were a little off.

The reason that the disk that didn't work on your Mac did work on your
IIgs could be attributed to higher tolerances in alignment and/or
magnetic field strength needed your IIgs drive than the Mac drive.

--
 Jeff Blakeney - Dean of the Apple II Unversity on A2Central.com