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From: c164-al@katerina.uucp (Joon Song)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Formatting a 1.44 MB disk to 720 kB...how?
Message-ID: <1991May17.081931.7014@agate.berkeley.edu>
Date: 17 May 91 08:19:31 GMT
References: <1991May16.220514.23423@ariel.unm.edu>
Sender: root@agate.berkeley.edu (Charlie Root)
Reply-To: c164-al@katerina.UUCP (Joon Song)
Organization: University of California, Berkeley
Lines: 25

In article <1991May16.220514.23423@ariel.unm.edu> ee5391aa@triton.unm.edu (Duke McMullan n5gax) writes:
>Just that...how?  For background, I have a 12MHz `286 box, which runs messdos
>3.3 with 4dos.  Drive A: is a high-density 5.25" floppy; drive B: is a high-
>density 3.5" microfloppy.  Can this be done?  Am I staring right through the
>answer, which is sitting right there in the doc.s for all to see?
>
>						Thanks,
>						    d

It seems that most 3.5" drives look for a hole in the disk casing to 
determine the density of the media.  So if you want to format a high-density
3.5" disk to 720K, just cover the high density hole with some scotch tape. 
Now you have a high density disk which looks like a double density disk to
the disk drive.  However, if you take scotch tape off and uncover the high
density hole, the disk will probably be unreadable on most machines.

Now some people out there are probably going to say something like:
  "all you need to do is type 'format b: /t:80 /n:9' from the command line".

Well, that may work on some machines (most notably IBM PS/2s), but on
most machines, a high density 3.5" disk drive will refuse to format a HD
disk to DD for the same reason that it will refuse to format a DD disk to 
HD.  (I know that doesn't make any sense, but it's true.)

Joon Song