DVD, which is also known as Digital Video Disc or Digital Versatile Disc is an optical disc storage media format, and invented and developed by Philips, Sony, Toshiba and Time Warner in 1995. Its main uses are video and data storage. DVDs are the same size as compact discs (CDs), but can save nearly seven times more information
DVD-term variations often shows how data is stored on the discs: DVD-ROM (read only memory) have data that can not read and written DVD-R and DVD + R (recordable) can record a data once and then function as a DVD-ROM DVD-RW (rewritable) data DVD + RW and DVD-RAM (memory) and delete all folders on several occasions. The wavelength of the lasers used by standard DVD is 650 nm [4] so that the light has a red color. DVD-Video and DVD-Audio consult properly formatted and structured video and audio content, respectively. Other types of DVDs, including those with video content that can be described as DVD data
History of DVD
In 1993, the two optical disc formats have been developed. One was the MultiMedia Compact Disc (MMCD), also known as sponsored CDi Philips and Sony, and the other was the Super Density (SD) disc, Toshiba, Time Warner, Matsushita Electric, Hitachi, Mitsubishi Electric, Pioneer, Thomson and JVC. Representatives of the SD camp approached IBM and asked advice from the file system to use the disk as well as trying to support them for saving data. Alan E. Bell, a researcher at IBMs Almaden Research Center have received this request, and also know the MMCD development project. Attention again to be a costly format war between VHS and Betamax in 1980, called a group of experts in the computer industry, including Apple, Microsoft, Sun, Dell and many others. This group is referred to as the Technical Working Group or Technical Working Group.
The TWG voted to boycott both formats unless the two groups agree on a standard convergence [5]. Lou Gerstner, chairman of IBM, was recruited to pressure the leaders of warring factions. Finally, software companies have gained, and a single format, now called DVD, was agreed. The TWG also collaborated with the Optical Storage Technology Association (OSTA) on the use of file system implementation of ISO 13346 (known as the Universal Declaration of Disk Format [] UDF) for use in new DVDs. Philips and Sony decided it was in the interest of avoiding another war of multimedia formats on your CD, and agreed to join with companies that support the Super Density Disc to release a single with two technologies. The specification was substantially similar to Toshiba and Matsushita's Super Density Disc, with the exception of the dual layer option (MMCD was option double layer on one side, while SD has a single layer, but eventually both sides) and EFMPlus modulation.
EFMPlus was chosen because of its high tolerance against the disc, such as scratches and fingerprints. EFMPlus created by Kees Immink (who also designed EFM) is 6% less efficient than the modulation technique originally used by Toshiba, which led to a capacity of 4.7 GB, unlike the original 5 GB. The result was the DVD specification of DVD movies and DVD-ROM computer applications in December 1995. DVD-Video format was introduced by Toshiba in Japan in November 1996 in the United States in March 1997 (testing the market, and Europe in October 1998 and Australia in February 1999.
In May 1997 the DVD Consortium was replaced by the DVD Forum, which is open to all other companies. [6] The specific DVDs have created and update the DVD Forum has published the so-called Books DVDs (eg, DVD-ROM DVD-Book Audio Book, DVD-Video Book, book, DVD-R, DVD-RW Book, DVD RAM Book, DVD HR Book, DVD-VR Book, etc.. Some of the specifications for the physical and optical properties of DVD optical disc can be downloaded freely available website.Also ISO, DVD + RW Alliance publishes the competing DVD standards, including DVD + R, DVD + R DL, DVD + RW or DVD + RW DL. The DVD formats are also ISO standards.
Some of the DVD specification (eg DVD video) are not publicly available and can be obtained only from DVD Format / Logo Licensing Corporation for an amount of U.S. $ 5000.Every subscriber must sign an agreement of confidentiality of certain information DVDs in the Book of proprietary and confidential.
Competitive DVD sites
