On Jun 19, 1:28 pm, "Stephen" wrote:
This is down to several factors.

Typical hard drives are hermetically sealed units which allow the platters
to spin at a higher RPM than would be the case for Zip or floppy drives.

If the hard disc was "floppy", you will find that it will distort if you
start spinning it at 5,400rpm (most laptop drives) or ar 7,200rpm (most
desktop hard drives) or even at 10,000rpm (high performance drives) the
floppy media would probably tear itself to shreds.

In addition, the gap between the read/write heads and the data surface is
very tiny, so any accidental bending of the disk surface runs the risk of
the heads destroying the data surface and making the owner kiss goodbye to
many Gigs worth of data. Having a hermetically sealed disk means there is no
issues with dust as there would be on a removable disc.

In addition, if the hard disc surface was to increase in diameter with the
high rotational speed, the head positioning motors would have to have a
tracking compensation algorithm so it knew where the data had "moved" to

So thats why hard discs have glass platters with a magnetic coating on it.

zip discs and floppies spin at much lower rpm as the disk is not
hermetically sealed and to avoid disc distortion that would otherwise occur
at higher RPM and also are of lower data density compared to todays HDD's og
500Gb to 1.5TB so head positioning on zip and floppies os not as critical as
it would be on a HDD.


Is it possible to hermetically-seal the soft disc of a floppy/zip? Of
course the spin speed would still have to be slow to prevent the soft
material from being injured. Right?

Is it also true that in order to have the same amount of storage
space, that the soft floppy material would need to be bigger in
diameter than the hard platter of an HDD?

IOW, is it possible for a soft floppy disc to have the same data
density as a hard HDD platter?