[comp.sys.mac.hardware] HD <-> Low D Fun

robs@ux1.cso.uiuc.edu (Rob Schaeffer) (02/20/91)

Someone where I work bought a load of high density disks.  But they have
some high density drives and some low density drives.  They formatted the
disks on a low density machine.  These disks can be read on low density
machines, but NOT on high density.  Is there anyway to fix this?  These
disks will get a lot of use, so tape over the hole is out.

Any ideas?

Rob

-- 
robs@ux1.cso.uiuc.edu

"My God, [static] it's full of [static] toasters..."
                           -- 2001, A Hardware Odyssey

dagraham@vax1.tcd.ie (02/22/91)

In article <1991Feb20.151150.17854@ux1.cso.uiuc.edu>, robs@ux1.cso.uiuc.edu (Rob Schaeffer) writes:
> Someone where I work bought a load of high density disks.  But they have
> some high density drives and some low density drives.  They formatted the
> disks on a low density machine.  These disks can be read on low density
> machines, but NOT on high density.  Is there anyway to fix this?  These
> disks will get a lot of use, so tape over the hole is out.
> 
> Any ideas?

Yes. First of all, low density drives use a much higher 'write' current than
high density ones, so a HD disc formatted low density may not be reformattable
again as HD because the weaker HD current may not be able to overwrite the
stronger low density signal, although I have been able to reuse discs formatted
in this way (and even format low density discs as high density, with a hole
drilled in the disc, but this is obviously not so reliable!)

Obviously if you can't reformat the discs high density, you could either-
1. Try a *big* magnet :-)
2. Fill up the hole somehow. Actually, 5.25" write protect metally labels work
quite well and stick well too. Or you could fill up the hole with goo- try
melted plastic or something. :-)

David Graham, JF Comp Sci, Trinity College, Dublin
dagraham@vax1.tcd.ie


#! r