CD-RW

Compact Disc ReWritable (CD-RW) is a rewritable optical disc format. Known as CD-Erasable (CD-E) during its development, CD-RW was introduced in 1997. While a prerecorded compact disc has its information permanently stamped into its polycarbonate plastic substrate, a CD-RW disc contains a phase-change alloy recording layer composed of silver, indium, antimony and tellurium. An infra-red laser beam is employed to selectively heat and melt the crystallized recording layer into an amorphous state or to anneal it at a lower temperature back to its crystalline state. The different reflectance of the resulting areas make them appear like the pits and lands of a prerecorded CD.

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A CD-RW recorder can rewrite 700 MiB of data to a CD-RW disc roughly 1000 times. CD-RW recorders can also write CD-R discs. Except for the ability to completely erase a disc, CD-RWs act very much like CD-Rs and are subject to the same restrictions; i.e., they can be extended, but not selectively overwritten, and writing sessions must be closed before they can be read in CD-ROM drive or players. The UDF 1.5 file system allows CD-RWs to be randomly rewritten, but limits disc storage capacity to roughly 530MB.

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Written CD-RW discs do not meet Red Book or Orange Book Part II standards for prerecorded or recordable CDs (e.g. reduced signal levels). Consequently, CD-RWs cannot be read in CD-ROM drives built prior to 1997. CD-R is considered a better technology for archival purposes as disc contents cannot be modified and manufacturers claim greater longevity.

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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 meta-data areas are cleared: PMA, TOC and pregap, comprising a few percent of the disc. Fast blanking will obviously be much quicker, and is usually sufficient to allow rewriting the disc. Full blanking removes traces the former data for example for confidentiality.

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Optical disc: In computing, sound reproduction, and video, an optical disc is flat, circular, usually polycarbonate disc whereon data is stored. This data is generally accessed when a special material on the disc (often aluminum) is illuminated with a laser diode....

Compact disc: Compact disc (or CD) is an optical disc used to store digital data, originally developed for storing digital audio. It is the standard playback format for commercial audio recordings today....

Silver: :This page is about silver the element. For the color, see silver (color)....

CD-RW related Images and Photos (experimental)

Paramore: Riot! CD	Paramore: Riot! CD	Adele:19 CD	Adele:19 CD
Phish: Joy CD	Phish: Joy CD	House CD-Rom	AVENTURA: LAST CD
BJORK: Volta CD	Bjork: Volta CD	Slash: Slash CD	Slash: Slash CD