The DVD Forum initially did not approve of the DVD+R format and claimed that the DVD+R format was not an official DVD format until January 25, 2008. The DVD+R format was developed by a coalition of corporations-now known as the DVD+RW Alliance-in mid-2002 (though most of the initial advocacy was from Sony). Higher speed variants, although compatible with lower writing speeds, are written to with the lowest error rate at the rated speed, similarly to CD-RW. ĭVD-RW media exists in the recording speed variants of 1× (discontinued), 2×, 4× and 6×. The writing of DVD-RW Version 1.2 is not backwards-compatible with earlier optical drives that have only been adapted to Version 1.1 and Version 1.0. There have been three revisions of DVD-RW known as Version 1.0 (1999), Version 1.1 (2000) and Version 1.2 (November 2003). To reconcile the two competing formats, manufacturers created hybrid drives that could read both - most hybrid drives that handle both formats are labeled DVD±R and Super Multi (which includes DVD-RAM support) and are very popular. DVD-R and DVD+R technologies are not directly compatible, which created a format war in the DVD technology industry. The dash format uses a " land pre-pit" method to provide sector address information.ĭVD "minus" R is not correct, according to DVD-R consortium recommendations it is, in fact, a dash (i.e. It has broader playback compatibility than DVD+R, especially with much older players. It is supported by most normal DVD players and is approved by the DVD Forum. The DVD-R format was developed by Pioneer in 1997.
Another benefit to using a rewritable disc is if the burning process produces errors or corrupted data, it can simply be written over again to correct the error, or the corrupted data can be erased.Īn internal DVD writer capable of burning either dash or plus discs
They are also ideal for home DVD video recorders, where it is advantageous to have a rewritable format capable of digital video data speeds, while being removable, small, and relatively inexpensive. RW discs are used to store volatile data, such as when creating backups or collections of files which are subject to change and re-writes. Thus, many discs have the RW logo, but are not rewritable.Īccording to Pioneer, DVD-RW discs may be written to about 1,000 times before needing replacement.
This can cause confusion because the ' DVD+RW Alliance' logo is a stylized 'RW'. Thus, "R" format discs are only suited to non-volatile data storage, such as audio or video. "R" format DVDs can be written once and read arbitrarily many times. The dyes used in each case are different as they are optimized for different wavelengths. This is used in conjunction with a higher numerical aperture lens. The smaller focus is possible with a shorter wavelength 'red' laser of 640 nm, compared to CD-R's wavelength of 780 nm. These two changes allow more pits to be written in the same physical disc area, giving higher data density.
The larger storage capacity of a DVD-R compared to a CD-R is achieved by focusing the laser to a smaller point, creating smaller 'pits' as well as a finer track pitch of the groove spiral which guides the laser beam.