Many medium sized business organizations have vaults

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Unformatted text preview: d/write head assembly either reads data, or writes data on the tape. It is a single unit having one read/write head for each tape track. Therefore, the read/write head assembly of a 9-track tape drive will have a set of nine heads. Each head operates independently and stores information on nine parallel tracks, parallel to the edge of the tape. This method of storing data in adjacent bit configurations is known as, parallel representation. In parallel representation, data are read or written a byte at a time. The two vacuum channels of the tape drive are designed to take up slack tape, acting as buffers to prevent the tapes from snapping or stretching when starting from a stationary position or slowing down from full speed. Several methods are used to prevent tape damage from sudden bursts of speed and different tape drives may use different mechanisms for this purpose. Magnetic tape reels are commonly used as archival storage for off-line storage of data and for exchange of data and programs between organizations. They are mainly used in organizations having large computing systems such as mainframe systems because the tape controller and tape drives used for magnetic tape reels are bulky and expensive. Many medium-sized business organizations have vaults containing several thousands of these tape reels. For example, a large insurance company may have a storage area containing over 50,000 magnetic tape reels. However, the magnetic tape reels are fast getting replaced by tape cartridge, streamer tape, and digital audio tape because these new magnetic tape storage devices are more compact, cheaper, and easier to handle and use. Half-inch Tape Cartridge Magnetic tape reels are suitable for use only with large and medium size computers. The same magnetic tape is used in smaller computer systems in the form of tape cartridges. As shown in Figure 8.9, these tape cartridges look very similar to the video cassettes used in the familiar home VCRs (video cassette recorders). The tape drives of these tape cartridges are also very simil...
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This document was uploaded on 04/07/2014.

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