the compact disc is an optical disc that is used for storing data. It is a small disc that can store large amounts of information. It can be accessed y a computer or a video compact disc (VCD) player. All compact discs look similar but different applications need different standards A standard compact disc is 12 cm in diameter. Compat diss can hold up to 650 MB of data. This is equivalent to 12,000 images or 2,00,000 pages of text. CDs are faster than magnetic tape as tracks on a CD are directly accessible. The CD formats available in the market are CD audio, compact disc read only memory (CD-ROM), CD-ROM extended architecture (CD-ROMXA) video CD, CD interactive (CD-I), etc. CD-ROMs ore used to store computer software. CD-ROMs in libraries contain periodical indexes, abstracts, statistics
4 directories, and other complete texts
Invention of the CD
The CD was invented by James T.Russell in 1965 He invented a remote-control battleship at the age of six years. He was fond of listening to music and wanted to improve the sound
records He decided to record and replay sound without physical contact between the parts. He used light and with the knowledge of digital data recording he was successful in the invention of a digital to optical y of phonograph recording system in 1970.
Through the 1970s Russell continued to refine the CD-ROM, adapting it to any form of data. Later, Sony es realised the implications f CDs and purchased the licenses. CDs became and other audio compani popular in 1983 In 1988, CD-Vs were introduced by manufacturers. They carried visuals with audio They can be attached to a special player and a TV set.
Types of CDs
There are three main types of CDs CD-DA: These are the standard can be played on any CD digital audio be played on CD R machines and computers manufactured read only mode CDs and player or computer CD-R: These are recordable CDs and can but not all CD digital audio players. . CD-RW: These are rewriteable CDs. They can only be played on CD-RW compatible machines and computers.
Digital versatile disc or digital video discs (DVDs) evolved from CD and related technologies. The DVD was devised by many companies like IBM, Sony, Philips, Toshiba, Matsushita, etc. The combined DVD format was launched in September 1991. DVD is a popular opitcal disc storage media format used for data storage DVDs look similar to CDs but they store cight times more data They are miainly used for storing movies, software and graphios files.