Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.csd.uwm.edu!leah!rpi!crdgw1!ge-dab!peora!tarpit!bilver!bill
From: bill@bilver.UUCP (Bill Vermillion)
Newsgroups: comp.sys.ibm.pc
Subject: Re: 3.5" High-Density Woes
Keywords: penny wise, pound foolish
Message-ID: <292@bilver.UUCP>
Date: 23 Aug 89 14:19:28 GMT
References: <1001@apctrc.UUCP> <5221@mtuxo.att.com>
Reply-To: bill@.UUCP (Bill Vermillion)
Distribution: usa
Organization: W. J. Vermillion, Winter Park, FL
Lines: 15

In article <5221@mtuxo.att.com> gjp1@mtuxo.UUCP (XMRK4-G.PATEMAN) writes:
>
>   ...           It's just that the 300 Oersted magnetic coating of an LD
>disk can't hold the signal the same way an HD's 600 Oe coating can.

Actually it is the higher current causing self-erasure on the inner tracks
because of the lower coercivity of the DD media.  Because the HD has higher
coercivity we can resolve a "tighter pattern", but require the higher current
to write.  It's not the retentivity that makes the real difference but that we
have to pound on it much harder to make it accept the signal in the first
place.
-- 
Bill Vermillion - UUCP: {uiucuxc,hoptoad,petsd}!peora!tarpit!bilver!bill
                      : bill@bilver.UUCP
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