Magneto-optical drive

A magneto-optical drive is a kind of optical disc drive capable of writing and rewriting data upon a magneto-optical disc. Both 130 mm (5.25 in) and 90 mm (3.5 in) form factors exist. The technology was introduced commercially in 1985. Although optical, they appear as hard disk drives to the operating system and can be formatted with any file system. Magneto-optical drives are common in some countries, such as Japan because of the success of the Sony MiniDisc, but have fallen into disuse in other countries.

Technical aspects

Early drives are 130 mm and have the size of full-height 130 mm hard-drives (like in the IBM PC XT). 130 mm media looks similar to a CD-ROM enclosed in an old-style caddy, while 90 mm media is about the size of a regular 3½-inch floppy disk, but twice the thickness. The cases provide dust resistance, and the drives themselves have slots constructed in such a way that they always appear to be closed. Original MO systems are WORM (write once, read many), and later systems are read/write.