Re: Disk imaging

["Roger Johnstone" <rojaws@es.co.nz>]

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In article <38b1d88d$1@news1.svn.net>, "Paul Grammens" <grammens@svn.net>
wrote:

>
>Rubywand <rubywand@swbell.net> wrote
>>
>>      There are a number of factors which impact useful life of software on
>diskette. For instance, software on a 3.5" diskette is likely to have a much
>shorter life than a that on 5.25" diskette.


>That's interesting, I would have thought the other way around, just based on
>the better protection and more advanced technology of the 3.5" diskette.
>Any idea why the 3.5" diskettes are less reliable?
>-Paul


I think the more advanced technology is the problem. As you increase the
density of the data stored in the same area you are going to have less and
less margin of error. Doing a quick measurement, a 3.5" floppy disk has
about half the useable surface area of a 5.25" disk. An Apple double density
5.25" drive (using 40 tracks) stores 160KB per side, a double density 3.5"
stores 400KB per side. That's 2.5 times more data in the same area. A high
density disk stores 5 times more. Even with better disk quality and higher
density magnetic heads, something has to give.

(Just don't ask me how they do it in drives like the Zip disk, which is
really just an overgrown floppy disk)


Roger Johnstone, Invercargill, New Zealand
http://homepages.ihug.co.nz/~rojaws
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There are two ways to write error-free programs. Only the third one works.