Computing (FOLDOC) dictionary
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hardware, storage Plastic or glass disks coated with a
compound (often TbFeCo) with special properties. The disk is
read by bouncing a low-intensity laser off the disk.
Originally the laser was infrared, but frequencies up to blue
may be possible; the shorter the wavelength the higher the
possible density. The polarisation of the reflected light
depends on the polarity of the stored magnetic field.
To write, a higher-intensity laser is used to heat the
material up to its Curie point, allowing its magnetisation to
be altered and "frozen" as it cools.
(1995-03-15)