PC Hardware in a Nutshell, 3rd Edition

DVD-RAM

The DVD-RAM standard is backed by Hitachi, Matsushita (Panasonic), and Toshiba, which until late 2001 had the writable DVD market all to themselves. Although DVD-RW and DVD+RW drives became widely available from several vendors by late 2001, relative to those writable DVD standards, DVD-RAM has several advantages for use in computers, including superior defect management, use of zoned CLV (PCAV) for faster access, and greater media protection via a cartridge. A DVD-RAM disc can be rewritten at least 100,000 times. Alas, only a tiny percentage of older DVD-ROM drives and almost no DVD players can read DVD-RAM discs.

First-generation (DVD-RAM Book 1.0) DVD-RAM drives began shipping in mid-1998, and used a mix of phase-change and magneto-optical technology to record 2.58 billion bytes per side on rewritable media. These discs are not readable by older DVD players and drives, although some recent DVD-ROM drives will read them. Second-generation (DVD-RAM Book 2.1) DVD-RAM drives, which began shipping in late 2000, read and write both original 2.6/5.2 GB DVD-RAM discs and 4.7/9.4 GB DVD-RAM discs.

Several DVD-RAM media types are available. Single-sided 2.6 GB discs are available in Type 1 (sealed) or Type 2 (removable) cartridges. Single-sided 4.7 GB discs are available in Type 2 cartridges. Double-sided 5.2 GB and 9.4 GB discs were originally available only in Type 1 cartridges, but are now available in Type 2 cartridges as well. In late 2002, noncartridge 4.7 GB and 9.4 GB DVD-RAM ...