Minor fix to Mtools patch for 3.5" disks

Gary S. Trujillo gst at gnosys.UUCP
Sat Aug 27 03:52:39 AEST 1988


In article <320 at uncle.UUCP> jbm at uncle.UUCP (John B. Milton) writes:
>In article <56 at gnosys.UUCP> gst at gnosys.UUCP (Gary S. Trujillo) writes:
>>In article <611 at bacchus.UUCP> darren at bacchus.UUCP (Darren Friedlein) writes:
>>>...
>>>One thing I'd like to find is a program like MsdosF.sh that will format
>>>3.5" disks.  Anyone know how to do this?
>>
>>For that matter, does anyone know how to format 5.25" floppies at 360K?
>>Far as I know, /usr/bin/MsdosF.sh will only format 320K (8-sector) disks.
>
>Well, too bad. The UNIX driver will only format (or use) an even number of
>sectors...

But don't standard MS-DOS floppies have 9 sectors?  I can read and write
them fine using either mtools or the DOS-73 coprocessor.

Shortly after posting my question, I got a very detailed response from
Roger Abrahams at Marquette University, going into basic theory of operation
of floppy drives and what all is actually on a floppy disk besides the actual
data.  Not only did Roger point out that one could format a 10-sector disk
with nine sectors actually allocated, but gave the command for doing it:

	md_format -9 /dev/rfp020

("md_format" is normally called from /usr/bin/MsdosF.sh)

-- 
Gary S. Trujillo			      {linus,bbn,m2c}!spdcc!gnosys!gst
Somerville, Massachusetts		     {icus,ima,stech,wjh12}!gnosys!gst



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