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From: usenet@cps3xx.UUCP (Usenet file owner)
Newsgroups: comp.sys.amiga
Subject: Re: DD/HD Disks
Message-ID: <6880@cps3xx.UUCP>
Date: 12 Mar 90 17:04:26 GMT
References: <7929@sdcsvax.UCSD.Edu> <1462@grape3.UUCP>
Reply-To: dailey@cpsin1.UUCP (Chris Dailey)
Distribution: na
Organization: Engineering, Michigan State Univ., E. Lansing
Lines: 39

In article <1462@grape3.UUCP> king@cell.mot.COM (Steven King) writes:
>In article <7929@sdcsvax.UCSD.Edu> bruss@odin.ucsd.edu (Brian Russ) writes:
>>	In a recent mailorder catalog I received, "High Density"
>>disks were advertised -- double sided, able to hold 2Meg of data.
>>The ad mentioned that Macs and IBM (of some varieties) can use these
>>-- can an Amiga?
>
>Yes and no.  Yes, you can stick them in an Amiga and use them normally.
>No, you can't put 2 Meg of data on them.  The disk-drive hardware just
>isn't designed to write higher-density data.  As far as the Amiga is
>concerned, you'll just be using a standard floppy.
[...]
>If you're not part of the solution, you must be    | Steve King  (708) 991-8056
[...]

(Part of this information is as I remember it from a PC-Magazine issue,
the number of which I can't remember.  Either an '89 or '90 issue.)

I believe that high density disks have more coating on them that is more
sensitive to the electrical impulses of a floppy drive write.  High
Density drives use lower strength impulses that may not be strong enough
to be read on a double density drive.  This is why they say you can use
a DS/DD disk on a HD drive but can not then go back and use that disk on
a DD drive.  I have in practice had only minimal problem with this.

But the question is using HD media on DD drives.  Since the coating on
the HD media is more sensitive, when a DD drive writes to HD media, the
media is more likely to modified by a write on an adjacent track.  I
have not actually 3.5" HD disks on a (3.5") DD drive, so I can not tell
you for sure of the reliablility, but there are problems trying to use a
5.25" HD disk on a 5.25" DS drive.

So, give it a try and let us know how it works.

 _   /|
 \`o.O'    Chris Dailey, Amiga Enthusiast
 =(___)=   dailey@cpsin1.cps.msu.edu
    U      - "Meow."
(Bill the Cat not original--imitation intended as a form of flattery.)