Recordable DVD (sometimes called writable DVD) is a DVD technology that allows a PC user to write data one or more times to a DVD with the PC's DVD drive. Among the various formats available are: DVD-RAM (DVD-Random Access Memory), a rewritable format that can be rewritten over 100,000 times; DVD-R (DVD-Recordable), a record-once format; DVD-RW (DVD-Rewritable) and DVD+RW (DVD-Rewritable), two similar, but incompatible formats that can be rewritten numerous times; and DVD Multi, a rewritable format that will enable the other formats to play in its drives.
Panasonic, Philips, and Pioneer have recently released three versions of recordable DVD. All three of the systems use a red laser, which has a 650-nanometer (nm) wavelength. Write once, read many (WORM) versions are written with organic dye-based media, and rewritable versions are written with phase change technology. Single-sided writable DVD disks, like the non-recordable version, can store 4.7 gigabytes (GB) of data.
Recordable DVD formats abound and conflicts remain a problematic issue. Two industry coalitions are backing different and largely incompatible versions: the Recordable DVD Council follows the recommendations of the DVD Forum (whose members include Hitachi, Pioneer, and Panasonic) to back DVD-RAM, DVD-RW, and DVD-R formats; and the DVD+RW Alliance, whose members include Hewlett-Packard, Dell, and Sony support the DVD+RW format. A newer standard, Blu-ray, has been developed as a possible replacement for recordable DVD.