The readable surface of a compact disc includes a spiral track wound tightly enough to cause light to diffract into a full visible spectrum.

Standard CDs have a diameter of 120 millimetres (4.7 in) and can hold up to about 80 minutes of uncompressed audio or about 700 MiB of data.

Media type
︎Optical disc

Read mechanism
780 nm wavelength (infrared and red edge) semiconductor laser, 1200 Kibit/s (1×)

Standard
︎Rainbow Books

Developed by
︎Philips, Sony

The Mini CD has various diameters ranging from 60 to 80 millimetres (2.4 to 3.1 in); they are sometimes used for CD singles, storing up to 24 minutes of audio, or delivering device drivers.

Usage
︎Audio and data storage

Extended from
︎LaserDisc

Extended to
︎CD-RW / DVD

Capacity
︎Typically up to 700 MiB