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Unformatted text preview: owing three types:
1. Zip/Bernoulli Disks. In this type, a single hard disk platter is encased in a plastic
cartridge. A commonly used zip disk is of 3'/2 inch size having a storage capacity of
about 100 MB depending on the formatting style used by a particular computer system.
Its disk drive is called a zip drive. A zip drive may be of portable or fixed type. The fixed
type is a part of the computer system, permanently connected to it. The portable type
can be carried to a computer system, connected to it for the duration of use, and then can
be disconnected and taken away when the work is done. The zip disks can be easily
insertedanto or removed from a zip drive just as we insert and remove floppy disks in a
floppy disk drive or a video cassette in a VCR.
Disk Packs. A disk pack consists of multiple (two of more) hard disk platters
mounted on a single central shaft. Thus all the disks of a disk pack revolve together at
the same speed. As mentioned before, the disk drive of a disk pack has a separate
read/write head for each disk surface excluding the upper surface of the topmost disk and
the lower surface of the bottommost disk. These two surfaces are not used for data
recording in a disk pack. When not in use, disk packs are stored in plastic cases as shown
in Figure 8.22. They are of removable/interchangeable type in the sense that they have to
be mounted on the disk drive before they can be used, and can be removed and kept offline when not in use. That is, different disk packs can be mounted on the same disk-pack
drive at different instances of time. This gives virtually unlimited storage capacity to disk
Winchester Disks. A Winchester disk also consists of multiple (two or more) hard
disk platters mounted on a single central shaft. However, the main difference between a
Winchester disk and a disk pack is that Winchester disks are of fixed type. That is, the
hard disk platters and the disk drive are sealed together in a contamination-free container
and cannot be separated from each other. Thus as opposed to disk packs which have
virtually unlimited capacity, Winchester di...
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This document was uploaded on 04/07/2014.
- Spring '14