Compact Disc or CD

A compact disk (cd) is a popular form of digital storage media used for computer files, pictures, and music. The plastic platter is read and written to by a laser in a CD drive. It comes in several varieties including CD-ROM, CD-R, and CD-RW.



James Russell invented the compact disk in 1965. James Russell was granted a total of 22 patents for various elements of his compact disk system. However, the compact disk did not become popular until it was mass manufactured by Philips in 1980.

Other CD formats include CD-ROM [ C ompact D isc- R ead O nly M emory], a form of CD that is read (but not written to) by computer using a CD-ROM drive and that can contain computer programs and digitized text, sound, photographs, and video; CD-R [ C ompact D isc- R ecordable] and CD-RW [ C ompact D isc- R e W ritable], which can be written to one time and multiple times, respectively. Interactive CDs (CD-I, CDTV, and other formats) can store video, audio, and data. Photo CD is a format that holds digitized photographs and sound. There are also CD-ROMs that require special players with built-in microcomputers.



Other optical disk formats include digital versatile (or video) discs and videodiscs. A digital versatile disk (DVD) holds far more information than a CD. DVD players are backward compatible to existing technologies, so they can also play a CD (or CD-ROM), but a CD player cannot be used with a DVD (or DVD-ROM). The videodisc , or laser disk system, uses 12-in. (30-cm) disks for video recording. Its technology, unlike that of the CD, is an analog system that uses a laser to read a variable-width track, much like a conventional phonograph record.