HP StorageWorks Ultra Density Optical Storage - Manual (Page 46)

Glossary
46 HP StorageWorks 30ux Standalone UDO Drive User’s Guide
ultra density optical
UDO (Ultra Density Optical), like HP's DVD+RW, uses Phase Change technology in order to
achieve increased data density on a 130mm disk. Phase Change technology uses a laser to read
and write from the active layer on the disk. The recording process uses the laser to heat each
data bit to a specific temperature. One temperature allows the bit to form a crystalline
(reflective) mark and a different temperature allows the bit to form an amorphous (less
reflective) mark. Data is read by using a low power laser beam to detect the difference in the
levels of reflectivity recorded on the disk.
write-once or WORM
An additional operating mode available with multifunction drives. When a write-once (WORM)
disk is inserted, the drive will write data, but will not write over data that has been previously
written. This feature is useful for applications that need permanent data security and audit trails.
write-protect
A feature that prevents data from being written to a disk. A write-protect tab is located on both
sides of the optical disk cartridge to enable write-protection on one or both surfaces of the disk.