The war over rewritable DVD standards heats up
Digital video disk technology has made few inroads into the drive market, and vendors are already hawking rewritable versions: DVD-RAM drives. It sounds great—big storage and rewritable. But a split among makers could leave buyers with incompatible rewritable DVD formats. As with any new medium, standards among the major manufacturers must be established. For the most part, standards for the DVD-ROM are set, but such is not the case for rewritable DVD. The biggest bone of contention
Digital video disk technology has made few inroads into the drive market, and vendors
are already hawking rewritable versions: DVD-RAM drives.
It sounds greatbig storage and rewritable. But a split among makers could leave
buyers with incompatible rewritable DVD formats.
As with any new medium, standards among the major manufacturers must be established.
For the most part, standards for the DVD-ROM are set, but such is not the case for
rewritable DVD. The biggest bone of contention is recording speed and technology.
The DVD Forum agreed on a rewritable format, said Mary Bourdon, principle analyst for
market researcher Dataquest Inc. of San Jose, Calif. But Sony Electronics Inc. of Park
Ridge, N.J., and Dutch company Philips Electronics NV splintered from the group to develop
their own standard, called DVD+RW, which wont require a cartridge to house the disk,
she said.
But the two major camps, led by Sony and Panasonic Communications and Systems Co. of
Secaucus, N.J., are locking horns on the issue of storage capacity: DVD-RAM offers 2.6G;
DVD+RW offers 3G, Bourdon said.
Hewlett-Packard Co., Mitsubishi Electronics Inc. of Cyprus, Calif., Ricoh Corp. of West
Caldwell, N.J., and Yamaha Corp. of America of San Jose, Calif., joined Sony and Philips
in rejecting a DVD-RAM standard and will proceed with rewritable technology, which is
based on Philips and Sonys CD patents.
Panasonic and others will make products based on the DVD-RAM standard the DVD Forum
set. Key features of the DVD-RAM format include high capacity: 2.6G per single-sided disk
and 5.2G per double-sided disk. They must read DVD-RAM, DVD-ROM and DVD-recordable media
as well as offer backward read-compatibility with CD-ROM, CD-audio, CD-recordable and
CD-rewritable media.
RW technology has a tendency to accidentally erase data because of track jumping at
writing, a Panasonic spokesman said. The wobbled land-and-groove format or track structure
makes DVD-RAM technology more reliable, and the constant linear velocity (CLV) format
provides a large capacity and high-access speed, the spokesman said.
Panasonics LF-D101 DVD-RAM writes to DVD-RAM and the companys phase-change
dual drive disks, which are similar to CD-RW. It can read disks for DVD-RAM, DVD-ROM,
DVD-video, DVD-R, PD drives, CD-ROM, CD-R, CD-RW and CD-video. The drive has a data
transfer rate of up to 10.5 mega-bytes/sec, 120-millisecond average seek time and 2M
buffer.
The DVD-Max drive from Maxoptix Corp. of Fremont, Calif., is a rewritable storage drive
that can read CD-ROM, CD-R, CD-RW, DVD-ROM and DVD-RAM media thanks to a
dual-laser/dual-lens system. It writes to Type I 5.2G double-sided and Type II 2.6G
single-sided media and comes in four internal and external configurations.
It also records at fast data rates including 1.38 megabytes/sec for DVD-RAM media and
2.76 megabytes/sec for DVD-ROM media. Pricing starts at $799.
According to Sony, RW uses a constant angular velocity rotation method, so it offers a
faster spin rate and higher capacity of 3.0G compared with DVD-RAMs capacity of
2.5G.
Its a method used to spin a disk at a constant rate to reduce the time
spent waiting for the disk to spin up or down, said Bob DeMoulin, Sonys
marketing manager of value-added products.
Access times are slower with CLV, which requires that the drive motor be constantly
adjusted to compensate for the differences in rotational speeds between outer and inner
disk diameters, DeMoulin said.
Because the disk spins fastest at the outer edge and slower toward the center, the
motor must be constantly adjusted, which slows data accessing, said Glinka Werner, senior
director of marketing at Hitachi Optical Storage and Multimedia Products of Brisbane,
Calif.
Finally, if youre in the market for a rewritable DVD drive, wait and see how the
market shakes out. Only about 75,000 rewritable DVD units will ship this year, and only
DVD-RAM units are available.