A CD-ROM is a pre-pressed optical compact disc. The name is an acronym which stands for "Compact Disc Read-Only Memory". Computers can read CD-ROMs, but they cannot write to CD-ROMs which are not writable or erasable. This changed with the release of CD-R (recordable) and CD-RW (re-writable). The CD-ROM format was developed by Japanese company Denon in 1982. It was an extension of Compact Disc Digital Audio, and adapted the format to hold any form of digital data, with a storage capacity of 553 MiB.
From the mid-1990s until the mid-2000s, CD-ROMs were popularly used to distribute software for computers and video game consoles. Some CDs, called enhanced CDs, hold both computer data and audio with the latter capable of being played on a CD player.