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From: davidr@hplsla.HP.COM (David M. Reed)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 3.5" High-Density Woes
Message-ID: <5190035@hplsla.HP.COM>
Date: 24 Aug 89 18:42:54 GMT
References: <1001@apctrc.UUCP>
Organization: HP Lake Stevens, WA
Lines: 21

I provide support for a lot of DOS users, and this is one area I frequently
can not help them.  If they format a low density disc (360K) as a high
density disc (1.2M), they will typically get about 600K of bad sectors and
the rest is okay.

HOWEVER, the problem that I get called about is when they can no longer
get their data back off the disc.  It seems that many of the sectors DOS
had considered good when it formatted the disc are really somewhat 
questionable, and experience deterioration over time.  (Most of the users
who have had this problem used the wrong disc type by accident when they
formatted their disc, and generally I have found that Norton Utilities 
will not recover most of the data that ends up in these marginal sectors.)

I am now getting experience of the same kind of problem from those who
format a disc certified for 720K as 1.4M, creeping deterioration of many
sectors of the disc.

So my advise is:  If your data is valuable, and your time is valuable, and
the manufacturer will not certify the disc for the higher density (when
they stand to make more money for almost no more investment or resources),
then why take chances?  I wont.