Penguin
Annotated edit history of DVD version 13, including all changes. View license author blame.
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7 LawrenceDoliveiro 1 Optical disc format which is an evolution of the older CompactDisc format. Originally an [Acronym] for __D__igital __V__ideo __D__isc, then this was changed to __D__igital __V__ersatile __D__isc, then finally it was deemed to stand for nothing at all, so that it could be trademarked.
3 JohnMcPherson 2
3 (See DiskVsDisc)
2 StuartYeates 4
13 LawrenceDoliveiro 5 DVD is an evolutionary, rather than a revolutionary, development of the same basic CD technology. By the mid 1990s, red-light lasers had become cheap enough to be incorporated into mass-market technology (as had happened with infrared lasers at the time of the introduction of the original CD). The shorter wavelength allowed the data density to be increased. This, along with improvements elsewhere in the tracking and reading systems, etc allowed the total amount of data stored to be increased by [a factor of about 7|http://web.archive.org/web/20011024000121/www.mpeg.org/MPEG/DVD/General/Gain.html], while keeping the same physical dimensions of the disc. DVDs can also have two layers, and this doubles the data storage yet again.
7 LawrenceDoliveiro 6
8 LawrenceDoliveiro 7 Another difference is that the CD were originally developed as an audio format, which was then adapted to become a computer data format. Whereas the DVD was developed from the beginning as a computer data format, which also happens to be usable for video, audio and other applications. Thus, whereas with CDs the CD-ROM data format is a special variation of the basic CD-Audio format, with DVDs it is the other way round: all DVDs are effectively "DVD-ROM" discs, and the [DVD-Video|DVDVideo] format is a special case defined by a particular file structure on the disc.
11 LawrenceDoliveiro 8
9 Instead of the ISO9660 filesystem defined for CD-ROMs, DVDs are supposed to use a format called UDF. However, for backward compatibility, most DVDs still have an ISO9660 filesystem on them as well, albeit sharing the same file contents and layout as the UDF filesystem.
7 LawrenceDoliveiro 10
11 Now being used a lot more in the [PC] world as many computers come with DVD drives for reading or for read/write.
4 PeterHewett 12
12 LawrenceDoliveiro 13 To play most commercial DVD movies, you need the [DeCSS] tool. Most distros do not include this because of legal threats from the media industry, so you need to download it separately.
6 MattBrown 14
15 There are some [DVDWritingNotes] found in this Wiki.
10 LawrenceDoliveiro 16
17 !See Also
18 * Pioneer's [DVD Technical Guide|http://pioneer.jp/crdl/tech/index-e.html]