Hardware Reference
In-Depth Information
vendors, including HP, Philips, Ricoh, and many remarketers of OEM drive mechanisms. Although
DVD-RW has increased in popularity with the advent of faster burning times and easier operation,
DVD+RW is the most popular rewritable DVD format.
Table 11.15
lists the basic specifications for DVD+RW drives.
Table 11.15. DVD+RW Specifications
Note that DVD+R, the recordable version of DVD+RW, was actually introduced after DVD+RW.
This is the opposite of DVD-RW, which grew out of DVD-R. One of the major reasons for the
development of DVD+R was to provide a lower-cost method for permanent data archiving with
DVD+RW drives, and another was because of compatibility issues with DVD-ROM and DVD video
players being incapable of reading media created with DVD+RW drives. However, most standard
DVD-ROM drives or DVD players can read both DVD+R and DVD+RW media without problems.
The basic structure of a DVD+RW or DVD+R disc resembles that of a DVD-R disc with data written
in the grooves only (refer to
Figure 11.14
), but the groove is wobbled at a frequency different from
that used by DVD-R/RW or DVD-RAM. The DVD+R/RW groove also contains positioning
information. These differences mean that DVD+R/RW media offers more accurate positioning for
lossless linking, but drives made only for DVD+R/RW media can't write to other types of DVD
rewritable or recordable media.
Although some first-generation DVD+RW drives worked only with rewritable media, all current and
future DVD+RW drives are designed to work with both DVD+R (writable) and DVD+RW
(rewritable) media. The +R discs can be written only once and are less expensive than the +RW
discs.
Some of the features of DVD+RW include the following:
• Single-sided discs (4.7GB).
• Double-sided discs (9.4GB).
• Up to 4 hours video recording (single-sided discs).
• Up to 8 hours video recording (double-sided discs).
• Bare discs—no caddy required.
• 650nm laser (same as DVD-Video).
• Constant linear data density.
• CLV and CAV recording.
• Write speeds 1x-8x and higher (depending on the drive and media).
• DVD-Video data rates.
