On 9/27/07 9:24 AM, in article 9sidnTbAZIS0PWbbnZ2dnUVZ_qelnZ2d@comcast.com,
"glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote:
Michael J. Mahon wrote:
(snip)
If you're not sure, and you care about the permanence of your data,
HD media in DD 3.5" drives should be avoided.
As far as I understand it, it either will or won't write.
There is a very small probability of a partial write,
somewhat similar to a coin flip landing on the side.
As noted before, a DD 5.25" drive will *not* reliably write HD media.
With a factor of two in coercivity for 5.25in it is pretty much
zero chance. Note that core memory depends on half the current not
writing a bit for every write or read cycle.
And what really stinks is that 5.25in are hard to determine.
Just look at a 3.5", if it has a hole across from the write protect, it is
HD.
5.25in? Well, unless it is in the box, it is hard to determine (even if it
is in the box, see below). I got a shipment of new disks, no sleeves, in
plastic wrap, plus some other make that were labeled DSDD. I've found that
MANY HD 5.25" do not have hub rings. Some of these DSDD didn't have the hub
rings, and were in fact, DSHD. They would format fine in an HD drive, but
not in a regular drive.
However, I've had supposed HD disks (no hub rings from an HD box new) that
formatted great in a regular drive, but not to HD. So apparently even the
manufacturers get them mixed up.