If reformatting a 360Kb on a 1.2Mb drive that already has data formatted &
written with a
360Kb drive the following situation will occur if that floppy is
subsequently read
with a 360Kb drive.
the 48 tpi track will have an 96 track inside it
the 48 tpi drivehard will read average data from both the 48 and the 96 bits
inside it
=
######01010001010000100010000010000010##### <Old 360KB DATA 1/4 48tpi
track
######00000000000000000000000000000000##### <new formatted track 1/2 96tpi
track
######00000000000000000000000000000000##### <new formatted track 1/2 96tpi
track
######01010001010000100010000010000010##### <Old 360KB DATA 1/4 48tpi
track
=
|
+-------- Head position cannot distinguish
between 0 or 1
Furthermore the adjecent 48 tpi tracks will interfere with the 96data cause
the encoded magnets will
will start to merge. (Big magnet domains will make inroads into smaller over
time)
As Tony Duel stated: It may be important to know if the floppies were
brandnew or bulkereased (degaussed)
or if they were written with a 48tpi head before reformatting. If you
bulkerease them before reformatting
(reformat preferably several times) you may get away with it since you will
not get the interference from old
data. and the new format will be stronger. You may also have to write
identical data several times but only
with the 1.2 kb drive. Any writing of data with a 48tpi drivehead will put
you back to square one.
I circomvented this situation with separate floppies. One to transfer data
from system A (1.2mb) to System B (360Kb)
and another (formatted on the 360kb drive) to bring data from B to A.
For a more permanent solution I would look for an extra 360 Kb drive
Sipke de Wal
----- Original Message -----
From: David Vohs <netsurfer_x1_at_hotmail.com>
To: <classiccmp_at_classiccmp.org>
Sent: Sunday, March 26, 2000 9:31 PM
Subject: Re: Parallel port hard drives?
> >Did you start with a bulk-erased (i.e. with a degausser) disk? And >is it
a
> >real 360K disk (and not a 1.2Mbyte one)?
> >
> >-tony
>
> Yes, it was a real 360K disk, I just reformatted it in Windows (it will
let
> you choose between 1.2Mb or 360 formats).
> ____________________________________________________________
> David Vohs, Digital Archaeologist & Computer Historian.
>
> Computer Collection:
>
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Received on Sun Mar 26 2000 - 17:29:44 BST