CDRWs
CD-RW, or CD-ReWritable, is a type of compact disc designed for multiple write-erase cycles. It uses a phase-change recording layer composed of a chalcogenide alloy (commonly AgInSbTe) that can switch between crystalline and amorphous states when heated by a laser. Data are written by raising the laser power to crystallize small spots; erasing returns the spots to the amorphous state. Readout is by a conventional CD laser, with differences in reflectivity encoding the data. The discs have a nominal capacity of 700 MB, or about 80 minutes of audio, and are available in standard 120 mm diameter with 74 or 80 minute audio formats.
CD-RWs require a CD/DVD drive that can write to rewritable media; many modern drives support CD-RW, but
Lifespan: the writable layer is designed for roughly 1,000 to 10,000 write/erase cycles, depending on manufacturing
History and use: CD-RW discs were introduced in the late 1990s as a reusable alternative to CD-R.