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From: goldstein@carafe.enet.dec.com (Fred R. Goldstein)
Newsgroups: comp.sys.atari.st,comp.sys.ibm.pc
Subject: Re: IBM PC / ATARI ST Disk Screwed Up
Message-ID: <7624@shlump.nac.dec.com>
Date: 19 Jan 90 21:47:00 GMT
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Followup-To: comp.sys.atari.st
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Organization: Digital Equipment Corp., Littleton MA USA
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In article <2646@cunixc.cc.columbia.edu>, ia4@cunixd.cc.columbia.edu (Imran Anwar) writes...
>...One of the staff there solved the problem by "Formatting a Low Density 3.5" 
>Disk on a High Density Drive" command available in the menu. Sure enough,
>the floppy formatted as 720K on the 1.4M machine worked fine on the 720K drives
>including my Atari ST drive.
> 
>So I spent the whole night typing some reports and saved them on this floppy. 
>The next day, at school, I had to use the 1.4M drive PC as that is the one 
>connected to a Laserprinter. But, surprise, that very drive that had formatted
>the disk showed it to be blank (even though the files showed up on the 720K 
>drive PCs). It simply said, File Not Found.
> 
>What could be the problem?
>...My question(s). Any idea of what could have happened? Solution?

I own both an ST and a PClone witha 1.44 drive.  Unlike the one you
used, mine has no trouble at all reading/writing 720k formatted disks.
Unlike 5.25" disks, there's no difference in track size between the
two densities, just in track density and write current. 

Probably the 1.44 drive is broken!  But the other likely problem is that
you screwed up the disk by swapping IBM-formatted disks on the ST.
Remember that the ST uses disk serial numbers to determine media change.
MSDOS disks don't have serial numbers.  So swapping two MSDOS disks
on an ST, without inserting an intermediate Atari-formatted disk, will
make the ST think you've reinserted the same disk, and it'll use the
old FAT info.

I format disks on the ST using IBMFMT, a freeware utility that writes
MSDOS-formatted disks with the random serial number.  TOS 1.4 does the
same.  Other formatters don't, and you should be careful not to confuse
the ST serial number checker.
       fred
---
Fred R. Goldstein   goldstein@carafe.enet.dec.com 
                 or goldstein@delni.enet.dec.com
                    voice:  +1 508 486 7388