What is "cd-rw"

alt. (initialism of compact disk Compact Disk - Read writable Writable English) A form of digital media that is based on the use of a laser to read from a plastic disc. It can be written to multiple times. n. (initialism of compact disk Compact Disk - Read writable Writable English) A form of digital media that is based on the use of a laser to read from a plastic disc. It can be written to multiple times.

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.

CD-RWs also have a shorter rewriting cycles life (ca. 1,000) compared to virtually all of the previously exposed types storage of media (typically well above 10,000 or even 100,000), something which is less of a drawback considering that CD-RWs are usually written and erased in their totality, and not with repeated small scale changes, so normally wear leveling is not an issue.

Their ideal usage field is in the creation of test discs, temporary short or mid-term backups, and in general, where an intermediate solution between online and offline storage schemes is required.