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An optical jukebox is a robotic data storage device that can automatically load and unload optical discs, such as Compact Disc, DVD, Ultra Density Optical or Blu-ray disc and can provide terabytes (TB) and petabytes (PB) of tertiary storage. The devices are often called optical disk libraries, robotic drives, or autochangers. Jukebox devices may have up to 2,000 slots for disks, and usually have a picking device that traverses the slots and drives. The arrangement of the slots and picking devices affects performance, depending on the space between a disk and the picking device. Seek times and transfer rates vary depending upon the optical technology. Jukeboxes are used in high-capacity archive storage environments such as imaging, medical, and video. Hierarchical storage management is a strategy that moves little-used or unused files from fast magnetic storage to optical jukebox devices in a process called migration. If the files are needed, they are migrated back to magnetic disk. Optical disc libraries are also useful for making backups and in disaster recovery situations. Today one of the most important uses for jukeboxes is to archive data. Archiving data is different from backups in that the data is stored on media that will last up to 100 years. The data is usually written on Write Once Read Many (WORM) type discs so it can not be erased or changed.〔Mesnik, Bob "How to comply with the archiving regulations without paying an arm and a leg" http://www.imakenews.com/kin2/e_article000742009.cfm?x=b8v5FDQ,b25tl0b3,w〕 Jukeboxes typically contain internal SCSI or SATA based recordable drives (CD-ROM, CD-R, DVD-ROM, DVD-R, DVD-RAM, UDO or Blu-ray) that connect directly to a file server and are managed by a third party jukebox management software. This software controls the movement of media within the jukebox, and the pre-mastering of data prior to the recording process. Before the advent of the modern SAN and much cheaper hard disks, large-volume storage on DVD was more price-efficient than magnetic media. Jukebox capacities have greatly increased with the release of the 50 gigabyte (GB) dual layer Blu-ray (BD) format, with a road-map to increase to eight layers and 200 GB per disc. The current format, used in the DISC7000, allows 35 TB of storage from a single 700 disc jukebox. Optical disc libraries like the TeraStack Solution can store up to 142 TB of online and nearline data with a nominal power draw of 425 watts.〔Green Data Storage http://www.tmcnet.com/usubmit/2010/01/14/4572041.htm〕 These two units show the wide variance of product attributes. == History == One of the first examples of an optical Jukebox was the unit designed and built at the Royal Aerospace Establishment at Farnborough England. The unit had twin read/write heads, 12" WORM disks and the carousels were pneumatically driven. It was produced to replace the 1/2 inch magnetic tape devices that were being used to store satellite data. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Optical jukebox」の詳細全文を読む スポンサード リンク
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