A typical storage hierarchy pyramid is shown in

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Unformatted text preview: to pre-recorded tapes in image quality and sound because it has multichannel surround sound. In addition, it has multiple selectable language soundtracks and subtitles, voice-over commentaries by the movie's cast or director, and convenient random access to special features. 2. DVD-audio. It offers multiple choices of sampling rate and numbers of bits per sample. For super-high fidelity, the music producer might opt for two channels with 24bit sampling at a rate of 192 KHz. (Contrast the basic CD standard with its two channels and 16-bit sampling at 44 KHz.) The specification also supports up to six channels of multichannel surround sound with 24-bit sampling at a 48 KHz rate. Besides the improved audio features, the DVD-audio specification goes beyond CD by making provision for visual menus, still images, and video to accompany the audio program. Storage Hierarchy We have learnt about the various types of storages used with computer systems. We also saw that different types of storages have different capacity, speed of access, and cost per bit stored. As a single type of storage is not superior in speed of access, capacity, and cost, most computer systems make use of a hierarchy of storage technologies. A typical storage hierarchy pyramid is shown in Figure 8.28. It includes cache memory, main memory, secondary storage and mass storage. As we move up the pyramid, we encounter storage elements that have faster access time, higher cost per bit stored, and less capacity. A larger storage capacity, lower cost per bit stored, and slower access time are the results of moving down the pyramid. Thus, cache memory generally has the fastest access time, the smallest storage capacity, and the highest cost per bit stored. The primary storage (main memory) falls next in the storage hierarchy list. On-line, directaccess secondary storage devices such as magnetic hard disks make up the level of hierarchy just below main memory. Off-line, direct-access and sequential-access secondary storage devices such as magnetic tape, floppy disk, zip disk, WORM disk, etc. fall next in the storage hierarchy...
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This document was uploaded on 04/07/2014.

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