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From: hdrw@ibmpcug.co.uk (Howard Winter)
Newsgroups: comp.sys.ibm.pc.hardware,comp.multimedia,comp.misc,connect.audit
Subject: Re: Diffs between DD & HD disks
Message-ID: <1991Apr9.075828.2135@ibmpcug.co.uk>
Date: 9 Apr 91 07:58:28 GMT
Organization: The IBM PC User Group, UK.
Lines: 22

It was written as a joke, but actually it used to happen:
Memory chips were made which had more cpaacity than was needed
in the finished chip, and the different banks were tested.
Depending on which banks had faults, the connection from the chip to
the package was made, so that the good banks were being used, the
bad ones weren't.  Nowadays I don't think they do this.
BTW I understand the medium used in DD vs HD disks IS different,
and that the coercivity (the ease with which magnetism becomes
permanent) is the variable.  I have certainly never been able to
reformat an HD 3.5" to 1.44 once it has been formatted at 720,
and I believe that the switching of strength of magnetism used
is the reason  -  the weaker HD field cannot overcome the 720.

But I may be wrong...

Howard.
-- 
Automatic Disclaimer:
The views expressed above are those of the author alone and may not
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-- 
hdrw@ibmpcug.Co.UK     Howard Winter     0W21'  51N43'