Optical disc

This article is about digital storage media such as CDs and DVDs. For a similarly-named anatomic feature of the eye, see optic disc.
"Optical media" redirects here. For transmission media for light, see Optical medium. For broader definition, see optical storage.
The bottom surface of a 12 cm compact disc (CD-R), showing characteristic iridescence.
The optical lens of a compact disc drive.
LaserCard made by Drexler Technology Corporation.
Computer memory and data storage types
General
Volatile
RAM
Historical
Non-volatile
ROM
NVRAM
Early-stage NVRAM
Analog recording
Optical
In development
Historical
Optical discs
General
Optical media types
Standards
See also

An optical disc is a flat, usually[note 1] disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid of a beam of light. Optical discs can be reflective, where the light source and detector are on the same side of the disc, or transmissive, where light shines through the disc to be detected on the other side.

Optical discs can store analog information (e.g. Laserdisc), digital information (e.g. DVD), or store both on the same disc (e.g. CD Video).

Their main uses are the distribution of media and data, and long-term archival.
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