DVD+RW

A spindle with discs of the DVD+RW format

DVD+RW is a physical format for rewritable DVDs and can hold up to 4.7 GB. DVD+RW was created by the DVD+RW Alliance, an industry consortium of drive and disc manufacturers. Additionally, DVD+RW supports a method of writing called "lossless linking", which makes it suitable for random access and improves compatibility with DVD players.[1]

DVD+RW must be formatted before recording by a DVD recorder.

The rewritable DVD+RW standard was formalized earlier than the non-rewritable DVD+R (the opposite was true with the DVD- formats). Although credit for developing the standard is often attributed to Philips, it was "finalized" in 1997 by the DVD+RW Alliance. It was then abandoned until 2001, when it was heavily revised (in particular, the capacity increased from 2.8 GB to 4.7GB).•

Technical details

The recording layer in DVD+RW and DVD-RW discs is a phase change metal alloy (often GeSbTe) whose crystalline phase and amorphous phase have different reflectivity. The states can be switched depending on the power of the writing laser, so data can be written, read, erased and re-written. DVD-R and DVD+R discs use an organic dye.

The capacity of a single-layer disc is approximated as 4.7 × 109 bytes. In actuality, the disc is laid out with 2295104 sectors of 2048 bytes each which comes to 4,700,372,992 bytes.

The DVD+RW format is divergent from the DVD-RW format. Hybrid drives that can handle both, often labeled "DVD±RW", are very popular since there is not a single standard for recordable DVDs. There are a number of significant technical differences between the "dash" and the "plus" format, although most users would not notice the difference. One example is that the DVD+RW style Address In Pregroove (ADIP) system of tracking and speed control is less susceptible to interference and error, which makes the ADIP system more accurate at higher speeds than the Land Pre Pit (LPP) system used by DVD-RW. In addition, DVD+R(W) has a more robust error management system than DVD-R(W), allowing for more accurate burning to media, independent of the quality of the media. The practical upshot is that a DVD+RW writer is able to locate data on the disc to byte accuracy whereas DVD-RW is incapable of such precision.

Double layer

A double-layer DVD+RW specification was approved in March 2006 with a capacity of 8.5 GB.[2] Manufacturing support for rewritable dual-layer discs exists today. See link below:

Capacity comparison

DVD capacity
Diameter Disk Type Data sectors
(2,048 B each)		 Capacity
cm Bytes MiB GB
12 DVD-R, DVD-RW (SS-SL) 2,298,496 4,707,319,808 4489.250 4.7
DVD+R, DVD+RW (SS-SL) 2,295,104 4,700,372,992 4482.625 4.7
DVD-R DL (SS) 4,171,712 8,543,666,176 8147.875 8.5
DVD+R DL (SS) 4,173,824 8,547,991,552 8152.000 8.5
DVD-R DS, DVD-RW DS (SL) 4,596,992 9,414,639,616 8978.500 9.4
DVD+R DS, DVD+RW DS (SL) 4,590,208 9,400,745,984 8965.250 9.4
DVD-R DS (DL) 8,343,424 17,087,332,352 16,295.750 17.0
DVD+R DS (DL) 8,347,648 17,095,983,104 16,304.000 17.0
  • SL / DL – Single/Dual layer
  • SS / DS – Single/Double sided

See also

References

  1. ↑ Range Of Available Standards : DVD Burner Test: Seven Times The Capacity
  2. ↑ DVD+RW part 2: Dual Layer, volume 1; DVD+RW 8.5 Gbytes, Basic Format Specifications, version 1.0, March 2006

Further reading

External links

This article is issued from Wikipedia - version of the Sunday, March 20, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.