Useful Notes: DVD
The DVD, more technically accurately known as the Digital Versatile Disc, was already unofficially being referred to as the Digital Video Disc while being developed and up to launch but received the former name to reflect the non-video capabilities. Even by that point people were just using DVD as probably everybody does nowadays. Some people like to say that it's just DVD with no proper name but they're not fooling anybody. Like a Compact Disc, but it uses more sophisticated hardware note and different media compression that is able to store more data. (In addition, the terminology is slightly different; unlike how CD-ROM only referred to data CDs, DVD-ROM refers to all DVDs that aren't recordable or rewritable, regardless of what is stored on them.) Single-layer DVDs hold about 4.7 gigabytes, while double-layer and double-sided discs can hold up to 9.4 gigabytes, and double-layer double sided discs can hold about 18 gigabytes. Conventional CD players cannot play DVDs, but DVD players can play CDs. Drives designed to read and write both CDs and DVDs are common and inexpensive; as of early 2009, most new personal computers have DVD writers fitted, and dual writers are generally easier to find than plain DVD-ROM or DVD-ROM/CD-RW combo drives. In addition, both the competing DVD-R(W) (developed by the DVD Forum itself as with DVD-ROM) and DVD+R(W) (developed by the DVD+RW Alliance note ) formats are generally supported by modern DVD writers. DVDs are now common installation media and provide reasonable quality video (in comparison to hi-def programming and Blu-ray; compare DVD to its forerunner, VHS, and the leap in quality is pretty astonishing.) The format is used by the vast majority of PlayStation 2 games, Xbox games, and Xbox 360 games (the PlayStation 3 uses Blu-ray.) It's also a major standard for video players; the first models came out in Japan in 1996, and in North America in 1997, and are still readily available today (sometimes for as little as US$20-30 for a small set-top player.) While Blu-ray was expected to replace it eventually, DVD's reach has been so great that this will take a while. Blu-ray was further hobbled by a format war with HD-DVD leading to even early adopters taking a wait-and-see stance, the 2008 global recession's effect on discretionary income and the convenience of online video sales/streaming sites leading to an end to any consumer demand for yet another new physical-media format, in that chronological order. On the plus side it helps that, unlike the switch from VHS to DVD, even the cheapest Blu-Ray players can play a standard DVD, due to the similarity in construction. Nintendo's GameCube and Wii optical formats are DVDs that always spin at the same speed from center to rim. This lowers their capacity slightly, and is an attempt to curtail piracy. note The high capacity of a DVD (about six-and-a-half times that of conventional compact disc) also offers an advantage in terms of computer gaming. Computer games that use up a lot of space can be loaded on just one or two DVDs, instead of multiple CDs. As an example, compare  2004 and Microsoft Flight Simulator X. The former takes up something like 1.5-3 gigabytes of space and has to be installed using four CDs. The latter takes up 15 gigabytes, but is installed using only two DVDs. For factoid's sake, the first two films ever released on DVD were Twister and Blade Runner: The Director's Cut. It should be noted that DVDs allow for Region Coding, something movie studios do to control their copyright and licensing (and screws fans of a show or movie over in turn if a disc turns out to be a No Export for You case.) Generally this has resulted law violations in certain countries and in turn resulted in the appearance of Region-Free DVD players. Even many brand name DVD players sold in the market today contain a key sequence one could enter to disable or change region as needed. Granted, the studios, ignoring the potential government lawsuits of these countries, attempted to counter the release of such devices by introducing an enhanced region-locking scheme. However, this scheme was so badly thought out that it not only didn't work with most of these region-free players, but these enhanced discs would also refuse to work on some region-locked players of the correct region. Sadly these companies continue to push this enhanced scheme, screwing over anyone who had bought a player that is affected but is otherwise still working fine.