CD-RW

CD-RW (Compact Disc-ReWritable) is a digital optical disc storage format. A CD-RW disc is a compact disc that can be written, read arbitrarily many times, erased, and written again. The technology was introduced in 1997.

CD-RW discs (CD-RWs) require readers that have more sensitive laser optics than are required to read plain CDs. Consequently, CD-RWs cannot be read in many CD readers built prior to the introduction of CD-RW. CD-ROM drives that bear a "MultiRead" certification claim compatibility.

CD-RW discs need to be blanked before reuse. Different blanking methods can be used, including "full" blanking in which the entire surface of the disc is cleared, and "fast" blanking in which only metadata areas are cleared: PMA, TOC and pregap, comprising a few percent of the disc. Fast blanking is much quicker, and is usually sufficient to allow rewriting the disc. Full blanking removes traces of the former data, often for confidentiality reasons. It may be possible to recover data from full-blanked CD-RWs with specialty data recovery equipment; however, this is generally not used except by government agencies due to cost.