An earlier removable, rewritable optical disk that also used magnetic technology. Introduced in 1985, magneto-optic (MO) media and drives are no longer manufactured. Refurbished drives and media are available from MaxOptix.com.Laser-Magnetic WritingA laser heats the optical bit to the Curie point, and a magnet changes the bit's polarity. The laser is on one side of the platter and the magnet on the other, which requires double-sided media to be manually flipped over to access the other side.Writing initially sets the bits to zero and then writes the data in a second pass. A single-pass LIMDOW (Light Intensity Modulated Direct OverWrite) method was later added, and many drives supported the more costly LIMDOW media.Laser ReadingA low-power laser light is reflected from the bits, and depending on their polarity, the difference in the light's rotation is sensed. See UDO, Kerr effect and optical disc.