Ten key promoters of the Digital Video Disk (DVD) standard have announced specifications both for DVD-RAM and write-once (DVD-R) high capacity disks.
The vendors, collectively called the DVD Forum, expect to release to the industry a format book with detailed specifications within the month and will follow with informational conferences around the world in the coming months, the forum said.
The DVD-RAM specifications call for a 5.2Gb double-sided disk and 2.6Gb single-sided 120-mm disk that is compatible with other DVD formats including DVD-Video and DVD-ROM, they said.
Under the DVD-RAM specifications, the disks will use phase-change technology, which means that signals are recorded to a film that is changed from crystalline to an amorphous state by the drive's laser. Differences in the reflectivity of the two states are read by the laser as the "0s" and "1s" of digital data.
In addition, the disks will use the so-called wobble-and-land groove-recording method, meaning that signals are recorded on both a disk's grooves and lands (area between the grooves), they said.
The write-once DVD-R format, meanwhile, calls for a single-sided 120-mm disk with a 3.95G-byte capacity, or about six times that of today's CD-R disks, and double-sided capacity of 7.9Gb, the forum said.
The forum also decided on a 80-mm version of the DVD-R standard, which will offer single-sided capacity of 1.23Gb and double that for a two-sided disk, they said.
The DVD Forum includes Hitachi Ltd., Matsushita Electric Industrial Co. Ltd., Mitsubishi Electric Corp., Victor Company of Japan, Pioneer Electronics Corp., Sony Corp., Toshiba Corp., Philips Electronics N.V., Thomson Multimedia and Time Warner Inc.