They are devices which use a combination of magnetic and laser technology to record and read information on Magneto-Optical drives come in versions called Magneto-Optical(MO) drive and a "Floptical" drive version.

The laser technology employed in these drives allows the data tracks to be controlled much better than your conventional magnetic drive. This means that we can pack the tracks on a MO drive much closer together than on the magnetic drive, and that the data is recorded at a higher density on the MO drives. The MO type of drive can store as much as 500MB on a disk in a cartridge. The disk is approximately 5 1/4 inches in diameter. The "floptical" floppy can usually store up to approximately 20 times as much as a conventional floppy, on a floptical disk the size of a 3 1/2 inch floppy.

The MO, Flopticals, WORM drives, and CD-ROM drives are similar in that they all use lasers to record information at high densities, and they are devices that you can move from PC to PC. However; WORM drives are writeable only one time, and the data cannot be changed. CD-ROM drives are similar, but you must have a "recordable" CD-ROM drive to write to a CD-ROM. MO and Floptical drives are supposed to be more portable, and the drives are supposed to be a reasonable alternative alternative to CD-ROM. They can also be used for backup and transfer of files in situations where you cannot use the Internet or other network to transfer files.

HOW DO MAGNETO-OPTICAL DRIVES WORK?

Well, I will give you the "general" concept of operation from a textbook approach. I cannot tell you how each manufacturer implements the exact technique.

1. The drive contains an "electromagnetic Read/Write Head" and a laser device.
2. The recording device is made of an aluminum layer and a crystalline metal alloy layer covered by a layer of plastic both on the top and the bottom.
3. Writing occurs by magnetizing a portion of the crystalline layer, and then focusing a laser beam on the surface of the disk. The laser heats the surface to a specific temperature known as the "curie point". At this temperature, the metalic crystals in the metal alloy can be moved by the magnetism of the write head. This magnetic force moves or aligns the crystals in one direction to represent a binary 0, and in the opposite direction to represent a binary 1.
4. Reading of the information occurs differently. First, the laser beam must be weaker to prevent changing of the data. The weaker laser beam is focused on the track that contains the data to be read. The crystals in the alloy polarize the light from the laser. This allows only light vibrating in a specific direction to go through the crystals. Light that passes through a crystal is then reflected from the aluminum layer back to a "photo diode" which senses the direction the light is polarized and translates it to a binary 1 or binary 0.
5. Obviously, the writing and reading of magneto-optical drives occurs at a very high rate of speed.