Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!elroy.jpl.nasa.gov!decwrl!waikato.ac.nz!comp.vuw.ac.nz!actrix!Roger.Sheppard
From: Roger.Sheppard@bbs.actrix.gen.nz
Newsgroups: comp.sys.atari.st.tech
Subject: Re: HD and DD floppies (Was: FTP problems)
Message-ID: <1991Mar30.133447.26083@actrix.gen.nz>
Date: 30 Mar 91 13:34:47 GMT
References: <MbvwaYm00VIE08N4wf@andrew.cmu.edu> <1991Mar29.010400.22832@jato.jpl.nasa.gov> <8bx06Ry00WAw88BWUu@andrew.cmu.edu>
Sender: Roger.Sheppard@actrix.gen.nz (Roger Sheppard)
Organization: Actrix Information Exchange, Wellington, New Zealand
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Comment-To: mc4c+@andrew.cmu.edu

Distribution:world 

In article <8bx06Ry00WAw88BWUu@andrew.cmu.edu> mc4c+@andrew.cmu.edu (Mark Choi) writes:
> > Excerpts from netnews.comp.sys.atari.st.tech: 29-Mar-91 Re: HD and DD
> > floppies (Was.. Van Snyder@jato.jpl.nasa (836)
> 
> > On 5.25 inch disks, DS/DD (360K) and DS/HD (1.2M) use different
> > coercivity
> > media, 300 Oersted media for DS/DD and 600 Oersted for DS/HD.  If you put
> > a DS/HD disk in a DS/DD drive, you might fry the heads.
> 
> This is not the case with 3.5 inch disks, however. Several articles have
> been written about the subject in many magazines, and when asked, the
> disk manufacturers admit as much. They try to add stuff about non-tested
> reliability, but what it comes down to is that the disks are identical,
> and if it formats and works O.K., then it has just passed the test. You
> save by doing the test yourself.

   Well here is my .02 cents worth, why is it that a lot of HD disks fail
when Formating on DD drives ??
   I am of the same opinion that HD disks do  have a higher Oersteds than
 DD disks.

   Also if HD disks have been Formated on a HD drive to 1.4 megs,
they can't be used on a DD drive, because of the lower Erase Flux of
DD drives.
   They can't Erase the data, because of the higher Oersted of the disk media
This has happened...



-- 
Roger W. Sheppard   85 Donovan Rd, Kapiti New Zealand...