Hardware Reference
In-Depth Information
quency 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 ex-
pensive 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-4x and higher (depending on the drive).
• DVD-Video data rates.
• UDF (Universal Disc Format) file system.
• Defect management integral to the drive.
• Quick formatting.
• Uses same 8-to-16 modulation and error-correcting codes as DVD-ROM.
• Sequential and random recording.
• Lossless linking. (Multiple recording sessions don't waste space.)
• Spiral groove with radial wobble.
• After recording, all physical parameters comply with the DVD-ROM specification.
DVD+RW technology is similar to CD-RW, and DVD+RW drives can read DVD-ROMs
and all CD formats, including CD-R and CD-RW.
With DVD+RW, the writing process can be suspended and continued without a loss of
space linking the recording sessions together. This increases efficiency in random writing
and video applications. This “lossless linking” also enables the selective replacement of
