Redundant Optical Storage System Using DVD-RAM Library
A Digital Virtual Disk (DVD) Random Access Memory (RAM) Redundant Array of Inexpensive Libraries (RAIL) optical storage system has been developed and tested at NTT Integrated Information & Energy Systems Laboratories. The RAIL storage system incorporates multiple DVD libraries that consist of dual DVD-RAM drives. Each DVD library utilizes a single mechanical robot picker for media loading and unloading. The current capacity of the single sided and single layered DVD optical media used in that system is 2.6 gigabytes. To increase the reliability of stored data and at the same time to eliminate the need for read after write verification, a process that can double the recording time, a RAID 4 algorithm has been implemented in the control unit of the RAIL storage system.