Date   : Sat, 05 Sep 1992 23:51:58 GMT
From   : haven.umd.edu!darwin.sura.net!cs.ucf.edu!tarpit!bilver!bill@uunet.uu.net (Bill Vermillion)
Subject: Re: 720K 5-1/4" diskettes

In article <1992Sep4.215455.5222@news2.cis.umn.edu> lemay@epx.cis.umn.edu
(Lawrence LeMay) writes:

>Apparently some of these 'quad' density disk drives are sensitive about NOT 
>having hub rings on the floppy. You will notice that High-Density floppies
>do not have these rings...

>So, is there a source of fairly high quality DS/DD floppies WITHOUT hub rings,
>for those of us that plan to format and use these disks as if they were Quad
>density disks?

Hub rings have nothing to do with the density, capacity, etc.

The reason hub rings are not needed on the high-density drives, is that
the drive spins on inserting the disk.  The hub motion is
self-centering because of the rotation.

The older designed drives, the full-height ones, used varying tapers on
the clamping cones.   These drives did NOT rotate upon insertion, and
the hub rings were the added re-inforcment to keep the center holes of
the disks from crimping.

You could really crunch the older disks too, as the drive was done via
a belt and you could really get some torque going in comparison to the
direct drive units.

I had disks (in the 1979/80) era that would spin in the full height
drives, but would not in the half-height direct drive units.


-- 
Bill Vermillion - bill@bilver.oau.org  bill.vermillion@oau.org
                - bill@bilver.uucp 
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