Magnetooptical disks and drives
Magnetooptical drives used magnetic and thermodynamic 
		properties to efficiently store data (see FAQ). It was not commonly used, 
		as it wasn't cheap. MO drives, in 3.5" or 5.25" standards were used in 
		some servers as testing/backup media or in expensive workststions. My 
		drive comes from IBM Power Series 850 PowerPC workstation.
		They were reliable, but quite slow and expensive. 
		Later magnetooptical disks evolved to GigaMO disks with enhanced 
		capacity (even 10GB) and Minidisc technology.