From: Dan Dugan <>
> Wow, that's amazing. It is a non-contact medium, the working surface
> being written and read by a laser beam in a magnetic field. The
> magnetic head contacts the other side of the disk, but I figure
> that's a highly polished head on a highly polished plastic surface
> (no coating like magnetic disks), so it appears it's not much
> affected by a little contamination.
The rating of MO media as good for a million rewrites is based on
projected wear from the magnetic source. It will not have worn through
the disk in that time, but is expected to start throwing the coated
record surface out of alignment by then.
Since a standard record head for regular magnetic media creates far more
wear (say like the one in a floppy disk drive) I assume that the contact
pressure of the magnetic source is much less. There's no reason it has
to be in actual contact, the laser determines the spot size.
Note the magnetic head is not involved in reading, only writing. So it
could be back there with all kinds of contamination and you could still
read the disk as long as the coated surface is not obscured by debris.
> Any stories of what -has- killed an MD disk?
I'm still working on killing one. No dead disks in 7 years of using them.
But a few other survivors:
A few years back a member of the minidisc newsgroup reported running his
car over one he'd dropped in a parking lot. And it played fine afterwards.
And I've talked to several folks who have managed to drop on into water.
Typically a mudpuddle. Rinsed out with clean water and dried they were
fine. And I, too consider that amazing, sooner or later someone is not
going to be so lucky.
We had a member in the early days of the group that reported recording
with a walkman MD in rain by just taping the seams in the recorder as
best he could. He had water running through his recorder while
recording. Sometimes pulling the tape to let the water back out.
Note, should any disaster happen to a disk of mine, I'd get the
recording copied off asp if I could, and then not continue to use the
disk. And if that all worked, thank my lucky stars and breathe a great
sigh of relief. Just because they are tough is no reason to abuse them.
The durability and reliability of the media is why I originally went to
the format.
Walt
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