Erasable storage disks operate partly on the optical and partly on the magnetic principle.
In the Thermo Magnets Optics process, a laser beam heats the magnetic plate to the crystallization point. At this temperature, a magnetically safe substance loses its magnetic properties. This erases the memory. As with any magnetic disk, the data is stored by magnetic fields. To read the data, the laser beam is used, which is deflected differently by the differently polarized fields.
The Compact Disc Magneto Optical( CD- MO) is specified in the Orange Book, is available in various sizes, is rewritable on one or both sides, operates with Constant Angular Velocity( CAV) and has a storage capacity of 128 megabytes ( MB) to 2.6 gigabytes( GB).