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From: wales@valeria.cs.ucla.edu (Rich Wales)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 3.5" drives
Message-ID: <22567@shemp.CS.UCLA.EDU>
Date: 5 Apr 89 06:23:26 GMT
References: <3647@uhccux.uhcc.hawaii.edu>
Sender: news@CS.UCLA.EDU
Reply-To: wales@CS.UCLA.EDU (Rich Wales)
Distribution: usa
Organization: UCLA CS Department, Los Angeles
Lines: 33

In article <3647@uhccux.uhcc.hawaii.edu>
webb@uhccux.UUCP (Thomas Webb) writes:

	Do 1.4 megabyte 3.5" drives really have problems reading and
	writing to 720k diskettes?  My office is buying a new computer
	and the salesman tells us that even with the proper driver most
	high-density 3.5 inch drives will not reliably read/write/
	format/etc. disks from the low density dirve in a NEC Multispeed
	portable.

To the best of my knowledge, your salesman is mistaken.

My initial impression is that he may be getting confused by the situa-
tion with 5.25" drives.  There *are* well-known problems with using
360K/5.25" diskettes in 1.2M/5.25" drives.  This is because the higher-
density diskettes have more tracks, and the heads on the high-density
drives are therefore narrower.

With 3.5" drives, though, the difference between 720K and 1.44M is in
the recording density on each track.  The number of tracks is the same
(80) for both kinds of disks.  Hence, the difficulties with 5.25" drives
handling both high- and low-density disks do *not* carry over to 3.5".

A properly functioning 1.44M/3.5" diskette drive should have no trouble
working with 720K diskettes.  Depending on your driver software, you
may have to specify some special flags on your FORMAT command in order
to format a disk in the manner you desire; but that's likely to be your
only problem.

-- Rich Wales // UCLA Computer Science Department // +1 (213) 825-5683
   3531 Boelter Hall // Los Angeles, California 90024-1596 // USA
   wales@CS.UCLA.EDU      ...!(uunet,ucbvax,rutgers)!cs.ucla.edu!wales
"Fate protects fools, little children, and ships named _Enterprise_."