ptical) An optical disc technology developed by Plasmon and later acquired by Alliance Storage Technologies (www.alliancestoragetechnologies.com), UDO is used for long-term data archiving. Available in both rewritable and write-once (WORM) 5.25" media, UDO uses blue laser optics and phase change recording. Introduced in 2003 with a 30GB capacity, storage was doubled to 60GB in 2007, and media life is expected to exceed 100 years.
Although similar to the rewritable CD/DVD drives used by consumers, UDO was designed with more robust engineering for commercial applications. For example, rewritable UDO uses eight layers in the disc compared to the typical four in consumer media.
Where Magneto-Optic Stopped
Designed to supersede magneto-optic (MO) disks in capacity, UDO's first blue laser 30GB drives offered a big storage jump over 9.1GB, the final format for MO drives. See blue laser
, phase change disk
and magneto-optic disk
UDO Cartridges and Libraries
Plasmon libraries hold hundreds of cartridges. The robotic mechanism in this unit grabs the cartridge and inserts it into one of six drives for reading and writing.
The polarity of the bits are either amorphous or crystalline, the latter appearing as a mix of white and black due to how different crystal alignments interacted with the laser beam. See phase change disc
. (Image courtesy of Alliance Storage Technologies, www.alliancestoragetechnologies.com)