There are two specifications for rewritable DVDs: DVD+RW and DVD-RW (Digital Versatile Disk Rewritable). Up to 1,000 times can be written to, deleted, and then written to again on a rewritable DVD-RW disc. The storage space on a DVD-RW disc is 4.7 Gigabytes. Although write-once codecs (like DVD-R) or professionally made discs are better supported by DVD players, most players can still handle rewritable optical discs like DVD-RW. A DVD-RW disc can only be written to using a suitable DVD-RW or Hybrid (DVD-RW) optical device.

There are two types of rewritable optical media: DVD-RW and DVD+RW DVDs. The information on a CD is read-only after it has been written until it is deleted and rebuilt. Discs are a bad option for keeping regularly changed files because you cannot modify files directly on them. Instead, the file is more appropriate for routine data copies.

There are three lasers in an optical disc reader that can write discs: a low-power laser for reading data, a medium-power laser for wiping out rewritable discs, and a high-power laser for writing data to a disc. The mirrored coating of a phase change metal alloy on the bottom of the disc is burned with a sequence of dots by a DVD-RW drive. This metal combination initially appears as a transparent crystalline structure. The metal is heated by a strong blazing laser until it melts, at which point it becomes opaque and cools. The scanning laser in the drive scans and decodes the digital data that is encoded in these dark areas. The medium-powered erase laser is used by the drive to heat the metal layer to the condensation point when it's time to delete a disc.