http://www.periphman.com/degaussing/degaussers/1200cd.shtml
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Now there is proof of gov't stupidity. Yeah, let's have a machine that
attempts to degauss a surface that doesn't use magnetism to store data
and then machine off the surface, too. Yeah, let's hang him, shoot him,
burn him and just for good measure then poison him. The unit you show
is clearly to degauss magnetic media and it uses machining to DESTROY
optical media (because magnetism isn't used).
Machining off the foil would be sufficient, just like burning it would
be just as effective. You are physically destroying the disc, not
erasing it. The degaussing is NOT to erase the media. It is to so
mechanically warp the foil that it cannot be read from or written to
thereafter. Magnetism is not used to record the data, but magnetism
(alternating, that is) is used to physically stress the aluminum so
whatever technique that is used to encode the data can no longer be
used. Weak degaussing that does not physically stress the aluminum foil
will do nothing to remove the data which does not use magnetism. Strong
degaussing that does physically stress the foil then makes it useless
thereafter - and that is NOT the same as erasure or reformatting which
presumes the media is still usable thereafter. Flipping magnetic
dipoles using AC current does nothing to alter the physical "pit" from
writing.
There is only one way that I could see that a degausser could erase
optical media: if it used such a strong alternating field that
alternated so fast that is flexed the aluminum foil at a rate fast
enough to cause thermal stress that would then emulate a fuzzy laser
that causes the dye "pit". Well, how does that differ from any other
way of physically distressing the disk to destroy it? Rather than use
heat, they use mechanical stress through magnetism by flexing the foil.
They aren't degaussing any magnetic media. They are using the magnetism
to destroy the film. Maybe. I doubt it. After all, when building
equipment to gov't specs, that doesn't mean you build logical equipment.
Reread the OP. The user wants to erase the disc, not destroy it.