Disk
From Wikipedia, the free encyclopedia.
A disk or disc (see below) is anything that resembles a flattened cylinder in shape. More specifically:
- In biology, an intervertebral disc is a cartilaginous joint between vertebrae in the spine of vertebrate animals.
- In mathematics, a disk is a geometrical object. See Disk (mathematics).
- A gramophone record (commonly "phonograph record" in U.S. English) is an analogue sound recording disc used on a gramophone or phonograph. It consists of a long spiral groove in on a side of a platter, commonly of vinyl, shellac or lacquer.
- The hard disk and floppy disk are magnetic storage media used in computers.
- A variety of optical storage media, such as the compact disc, DVD, and laserdisc, are used for digital data or video.
- Disc brakes are often used in automobiles.
- In astrophysics, an accretion disc or disk is a structure formed by material falling into a gravitational source.
- The Frisbee is a flying disc toy.
- The DiSC assessment is a psychological assessment used to determine individual's personality types and is often used in performance management and employment selection.
Disc or disk?
The divergence in spelling is due in part to the way in which the words originated. Disc came into the English language in the mid-17th century, from the Latin discus, and like already-existing words like whisc or risc, it was spelled with c; disk arose some time later, and was based on the original Greek root diskus. In the 19th century, disk became the conventional spelling for audio recordings made on a flat plate, such as the gramophone record; this usage gave rise to the modern term disk jockey. Early BBC technicians differentiated between discs (in-house transcription records) and disks (the colloquial term for commercial gramophone records, or what the BBC dubbed CGRs).
By the 20th century, the c-spelling was more popular in British English, while the k-spelling was preferred in American English. In the 1940s, when the American company IBM pioneered the first hard disk storage devices, the k-spelling was used. In 1979 the Dutch company Philips, along with Sony, developed the compact disc medium; here, the c-spelling was chosen, possibly because of the predominating British spelling, or because the compact disc was seen as a successor to the analogue disk record. Most likely it's because the spelling disc is acceptable to the French, just as Philips introduced the cassette in the 1960s under a French name, too.
Whatever their heritage, in computer jargon today it is common for the k-spelling to refer mainly to magnetic storage devices, while the c-spelling is customary for optical media such as the compact disc and similar technologies. Even in the computing field, however, the terms are used inconsistently; software documentation often uses the c-spelling exclusively.
Etymology: from Greek δίσκος, a flat round object athletes competed in throwing. See discus throw.