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HARD DISK
A computer storage medium that,
unlike a diskette, is permanently installed inside a computer. A
hard disk has a vastly larger capacity than a floppy.
More Detailed Definition:
A magnetic disk on which you can
store computer data. The term hard is used to distinguish it from
a soft, or floppy, disk. Hard disks hold more data and are faster
than floppy disks. A hard disk, for example, can store anywhere
from 10 to more than 100 gigabytes, whereas most floppies have a
maximum storage capacity of 1.4 megabytes.
A single hard disk usually consists of several platters. Each
platter requires two read/write heads, one for each side. All the
read/write heads are attached to a single access arm so that they
cannot move independently. Each platter has the same number of
tracks, and a track location that cuts across all platters is
called a cylinder. For example, a typical 84 megabyte hard disk
for a PC might have two platters (four sides) and 1,053 cylinders.
In general, hard disks are less portable than floppies, although
it is possible to buy removable hard disks.
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