Tertiary Storage - since they have a high capacity (about...

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Tertiary Storage Optical Disks Magnetic Tapes Optical Disks 1. CD-ROM has become a popular medium for distributing software, multimedia data, and other electronic published information. 2. Capacity of CD-ROM: 500 MB. Disks are cheap to mass produce and also drives. 3. CD-ROM: much longer seek time (250m-sec), lower rotation speed (400 rpm), leading to high latency and lower data-transfer rate (about 150 KB/sec). Drives spins at audio CD spin speed (standard) is available. 4. Recently, a new optical format, digit video disk (DVD) has become standard. These disks hold between 4.7 and 17 GB data. 5. WORM (write-once, read many) disks are popular for archival storage of data
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Unformatted text preview: since they have a high capacity (about 500 MB), longer life time than HD, and can be removed from drive -- good for audit trail (hard to tamper). Magnetic Tapes 1. Long history, slow, and limited to sequential access, and thus are used for backup, storage for infrequent access, and off-line medium for system transfer. 2. Moving to the correct spot may take minutes, but once positioned, tape drives can write data at density and speed approaching to those of disk drives. 3. 8mm tape drive has the highest density, and we store 5 GB data on a 350-foot tape. 4. Popularly used for storage of large volumes of data, such as video, image, or remote sensing data....
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