In computing, a CD (compact disc) is a digital optical disc data storage format. It was originally developed to store and play back sound recordings (CD-Audio), but later evolved to permit storage of other types of data.

A CD is a polycarbonate disc with a diameter of 120 millimetres (4.7 in) and a thickness of 1.2 millimetres (0.05 in). The disc can hold up to 700 MiB of data. The data is stored on the disc as a series of microscopic indentations. A CD-ROM drive can read CDs and, depending on the type of CD, may also write to them.…