[comp.sys.ibm.pc] 720 kB 5.25" floppies?

iiit-sh@cybaswan.UUCP (Steve Hosgood) (05/25/89)

In article <550@megatek.UUCP> hollen@eta.megatek.uucp (Dion Hollenbeck) writes:
>From article <3649@penet.UUCP>, by thomas@penet.UUCP (Thomas Aschan):
>> Does anybody have experience
>> with reading & writing 720 kB 5 1/4"
>> floppies?
>> 
>Yes, I have Shugart 565 5 1/4" drives which are 720kb.  I use them both
>as standard floppies and also with Fastback for backup purposes.
>I have needed to put "DRIVPARM /d:2 /h:2 /t:80" (check DOS manual for
>exact syntax since I am at work, not at home where the drives are) in
>my config.sys...

I've done this with Mitsubishi drives, and as you say, it works fine on an
XT... 

>....or if on an AT, use setup and tell
>it that they are 3 1/2" 720kb drives.  Unless you have some strange 
>format, the 720kb drives are 2 heads, 80 tracks, 9 sectors per track,
>exactly the same as the 3 1/2" drives currently popular.
>

PROBLEM: I tried to do this with my AT at work, but found that there's some
strange incompatibility between the drives (Mitsubishi) and the connector
from the AT's floppy controller. It *seems* (after a lot of checking) that
the AT controller has two drive selects and two motor-on lines in the ribbon
cable (or something like that) whereas my drive expects something a bit
different. Again, my data's at home so I can't give full details.

>One caveat, DRIVPARM does not work on DOS 3.3, but will work on 3.2.
>I spent lots of time figuring this one out, and I will never upgrade to
>3.3 because of it.

I seem to remember something posted recently about how to fix that problem.
Maybe some kind soul will repost the solution. It was really baroque, like
inserting several control-A characters in the DRIVPARM line or something..!

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Steve Hosgood BSc,                             | Phone (+44) 792 295213
Image Processing and Systems Engineer,         | Fax (+44) 792 295532
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