ReWritable

Rewritable refers to media or storage technologies that allow stored data to be erased or overwritten with new information, enabling the same medium to be reused multiple times. This contrasts with write-once media, such as most traditional CD-R, DVD-R, or ROM devices, where data cannot be overwritten after recording.

Common rewritable media include optical discs such as CD-RW, DVD-RW, and Blu-ray Disc in rewritable form (BD-RE). These use phase-change or similar materials that can switch between states to represent data, and require erasing before rewriting. Rewritable optical discs have reduced compatibility with older players and drive firmware compared with their write-once counterparts, but are widely supported by modern hardware.

Rewritable storage also exists in magnetic and solid-state technologies. Magneto-optical systems and some erasable magnetic tapes can be rewritten; flash-based storage such as USB flash drives and solid-state drives are inherently rewritable, though flash memory imposes limits on write-erase cycles and relies on wear leveling and garbage collection to extend life. In computing contexts, the term is also used to describe writable and erasable memory that can be updated post deployment, in contrast to read-only memory.

The technology has been used for data backup, software distribution, and archival workflows where data needs updating without replacing the medium. Standards bodies have defined formats for rewritable optical media, including CD-RW (Orange Book), DVD-RW, and BD-RE, with evolving performance and compatibility guarantees.