Magneto optical drive
The Magneto-optical drive (Bernoulli or floptical drive) looks similar to a floppy disk drive, and the disks follow the same general shape as a floppy disk.
The difference is in the way the floptical drive works. Whereas a floppy drive uses a magnetic Read/Write head to magnetise the ferrite coating on the disk, a floptical drive has a different coating, which needs a combination of heat and magnetic field for it to be polarised.
The coating is made of a metallic alloy, whose magnetic properties will only change when it is heated to melting point. The heat is applied by a laser, and the magnetic field by a standard Read/Write head, so, like a floppy disk, a small dot is magnetised.
The laser heats a much smaller dot than the one on a floppy disk, which means that a lot more data can be stored on a floptical disk than on a standard floppy disk.
A floptical disk can store at least 100Mb of data, compared with a floppy's 1.44Mb.
This type of disk and drive were used for backups and for transferring files from one computer to another. They are becoming much less common, because they have been overtaken by CD/DVD writers and USB flash drives.
Floppy disk working.
Floptical disk working.