What is a compact disk?
Since 1982, consumers had access to one of the large breakthroughs in media storage technology: a slender, round and glossy object known as a compact disk (CD). Also known as the optical disk, 4.724 inches (120 mm) round polycarbonate CD has largely replaced less reliable, but similar formats such as cassette tape and vinyl recording as a unit for digitally stored sound. Despite its size, one standard compact disk can accommodate up to 80 minutes of music. This remains the most advantageous and popular medium for sound recordings. CD-ROM, later version of the same technology, hold up to 700 megabytes (MB) data and is widely used by individuals and businesses for archiving important documents, photos and software.
The compact disc is made of a combination of polycarbonate plastic and a reflective layer of aluminum, gold or other metal. It was modeled after Laserdisc (LD), now-Medium,that resembles vinyl record in its size and CD in its composition. The information is "burned" on the metal layer of the CD with the laser, in the spiral direction from the inner part of the CD to the outer edge. These coded data or sound can then be accessible with optical drives such as CD players, DVD players and DVD recorders. Due to the low quality of the production of many compact discs, the coated CD surface or label can be scratched or contaminated to the extent that the information is irreversible; In most cases, however, the compact disc can be gently erased with a cloth without a government to remove any excess dirt and solve playback problems.
other compact disk formats serve many purposes. The mini CD, which is much smaller at 2.362 inches (60 mm) to 3.149 inches (80 mm), holds 24 minutes of sound and musicians often use them for music singles. Rewritten CD (CD-RW) has the ability to store the media, and then be "overwritten" or replaced by other data at a later date. CD-R, similar but not to get awayElna version, can only have information written on CD once.
6 Super Video CD (SVCD) is a lower high -quality alternative to a record DVD and is used to record video at a lower bit speed than a standard DVD. Although there are many alternatives, the CD-R remains the most popular version of the compact disk for its ability to contain many forms of information and music.