cdrw

CDRW, short for Compact Disc ReWritable, is a type of compact disc that can be written, erased, and re-written multiple times. It uses a phase-change recording layer that alternates between crystalline and amorphous states to represent data, unlike CD-ROM which is pre-stamped. Data is written by a drive that heats tiny areas with a laser; erasing is achieved by resetting regions to the amorphous state.

Capacity and compatibility: Typical capacities are about 650–700 MB (roughly 74–80 minutes). CD-RWs require a compatible drive and media; blank discs cost more than CD-Rs but less than DVDs, and not all drives can read every CD-RW.

Recording and file systems: CD-RWs support random-write and packet-writing modes. Data discs can be formatted with ISO 9660, Joliet, or UDF and written incrementally, allowing updates without recreating the entire disc.

Endurance and reliability: CD-RW discs are rated for around 1,000 rewrite cycles, depending on brand and usage. Data retention can be decades with proper storage, but performance may degrade with heavy scratches, heat, or poor handling.

Applications and limitations: CD-RWs were popular for data backup and short-term storage in the late 1990s and 2000s, but many consumer electronics players do not read CD-RWs reliably, and audio playback on CD-RWs is less common. With the rise of USB flash drives, external hard drives, and cloud storage, the use of CD-RWs has declined, though they remain used in some archival and legacy workflows.