MAGNETIC DISK

The era of the personal computer has seen the development of ever-morecompact data storage systems. One of the most versatile is the magnetic disk. Such a disk can be either rigid or flexible. Disks are available in various sizes. Hard disks (also called hard drives) store the most data and generally are found inside computer units. Diskettes are usually 3.5 inches (8.9 cm) in diameter and can be inserted and removed from digital recording/playback machines called disk drives.
The principle of the magnetic disk, on the micro scale, is the same as that of magnetic tape. But disk data is stored in binary form; that is, there are only two different ways that the particles are magnetized. This results in almost perfect, error-free storage. On a larger scale, the disk works differently than tape because of the difference in geometry. On a tape, the information is spread out over a long span, and some bits of data are far away from others. On a disk, no two bits are ever farther apart than the diameter of the disk. Therefore, data can be transferred to or from a disk more rapidly than is possible with tape.

A typical diskette can store an amount of digital information equivalent to a short novel. Specialized high-capacity diskettes can store the equivalent of hundreds of long novels or even a complete encyclopedia.

The same precautions should be observed when handling and storing magnetic disks as are necessary with magnetic tape.