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From: CXT105@psuvm.psu.edu (Christopher Tate)
Newsgroups: comp.sys.mac.misc
Subject: Re: Format floppy disks
Message-ID: <90243.104636CXT105@psuvm.psu.edu>
Date: 31 Aug 90 14:46:36 GMT
References: <1990Aug27.110119.2908@hellgate.utah.edu>
Organization: Penn State University
Lines: 42

In article <1990Aug27.110119.2908@hellgate.utah.edu>,
cyang%peruvian.utah.edu@cs.utah.edu (Cheng Yang) says:

>The floppy disks formatted by a Macintosh cannot be
>reformatted by an IBM PC.  And the floppy disks formatted
>by an IBM PC can't be reformatted by a Mac.  Does anyone
>here have any idea of solving this problem?

Just what do you mean when you say that the disks can't be reformatted?
Is is that the Mac *tries* to format the disks, but invariably fails?  If
this is the case, then the earlier suggestion of brushing the disk liberally
with a permanent magnet may well be your best bet.

However, I'm not sure I understand why you're having this problem.  I have
often reformatted Mac disks as IBM disks, and vice versa, with no trouble.

Check the densities of the disks you're using.  Are they double density (one
notch in the disk) or high density (two notches)?  If you try to format a
high density disk in drives that can't handle them (non-FDHD drives on Macs,
non-1.44 MB drives on IBM's), you'll have a lot of trouble.  The 800K drives
simply can't handle the greater remanence (sort of "strength") of the magnetic
medium on high density disks.

Oh, and just for general usefulness, here's how to force the Mac to reformat
ANY disk when you insert it.  Sometimes the Desktop file gets a bad sector
in it.  When this happens, the Mac will ordinarily try to rebuild the file,
after telling you it has to make "minor repairs."  Because of the bad sector,
this attempt fails, and so the Mac reports "unable to create desktop file,"
and ejects your disk without giving you a chance to "Erase Disk" to fix the
problem.  To get around this, do the following:

Hold down the command, option, caps-lock, and tab keys while inserting the
disk.  (You may also have to hold down shift; I don't remember offhand.)
This forces the Mac to bring up the disk initialization dialog, whether or
not the disk is readable.

-------
Christopher Tate                        |   "Oh wow:  not only is 57
                                        |    prime, but it's also
Bitnet: cxt105@psuvm                    |    divisible by three!"
Uucp: ...!psuvax1!psuvm.bitnet!cxt105   |
Internet: cxt105@psuvm.psu.edu          |    - a very sincere math major