A CD-R (Compact Disc-Recordable) is a variation of the Compact Disc invented by Philips and Sony. CD-R is a Write Once Read Many (WORM) optical medium, although the whole disk does not have to be entirely written in the same session.CD-R retains a high level of compatibility with standard CD readers, unlike CD-RW which can be re-written, but is not capable of playing on many readers.
The CD-R, originally named CD Write-Once (WO), specification was first published in 1988 by Philips and Sony in the 'Orange Book'. The Orange Book consists of several parts, furnishing details of the CD-WO, CD-MO (Magneto-Optic), and CD-RW (ReWritable). The latest editions have abandoned the use of the term "CD-WO" in favor of "CD-R", while "CD-MO" were used very little. Written CD-Rs and CD-RWs are, from a technical standpoint, fully compatible with the Audio CD (Red Book) and CD-ROM (Yellow Book) standards, although some hardware compatible with Red Book CDs may have difficulty reading CD-Rs and especially CD-RWs. They use Eight-to-Fourteen Modulation, CIRC error correction plus the third error correction layer defined for CD-ROM.