CD
Compact disc
"CD" redirects here. For other uses, see CD (disambiguation).
Compact disc (CD) is a digital optical disc data storage format released in 1982 and co-developed by Philips and Sony. The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. The first commercially available Audio CD player, the Sony CDP-101, was released October 1982 in Japan.
Compact Disc
The readable surface of a compact disc includes a spiral track wound tightly enough to cause light to diffract into a full visible spectrum
Media type Optical disc
Encoding Various
Capacity Typically up to 700 MiB (up to 80 minutes audio)
Read mechanism 780 nm wavelength (infrared and red edge) semiconductor laser, 1200 Kibit/s (1×)
Write mechanism 780 nm laser with a focused beam more powerful than one used for reading, 1200 Kibit/s (1×)
Standard Red Book
Developed by Philips, Sony
Usage Audio and data storage
Extended from LaserDisc
Extended to CD-RW
Standard CDs have a diameter of 120 millimetres (4.7 in) and can hold up to about 80 minutes of uncompressed audio or about 700 MiB of data. The Mini CD has various diameters ranging from 60 to 80 millimetres (2.4 to 3.1 in); they are sometimes used for CD singles, storing up to 24 minutes of audio, or delivering device drivers.
At the time of the technology's introduction in 1982, a CD could store much more data than a personal computer hard drive, which would typically hold 10 MB. By 2010, hard drives commonly offered as much storage space as a thousand CDs, while their prices had plummeted to commodity level. In 2004, worldwide sales of audio CDs, CD-ROMs and CD-Rs reached about 30 billion discs. By 2007, 200 billion CDs had been sold worldwide.[1]
From the early 2010s CDs were increasingly being replaced by other forms of digital storage and distribution, with the result that audio CD sales rates in the U.S. have dropped about 50% from their peak; however, they remain one of the primary distribution methods for the music industry.[2] In 2014, revenues from digital music services matched those from physical format sales for the first time.[3]
Contents
HistoryEdit
American inventor James T. Russell has been credited with inventing the first system to record digital information on an optical transparent foil that is lit from behind by a high-power halogen lamp.[4][5] Russell's patent application was first filed in 1966, and he was granted a patent in 1970. Following litigation, Sony and Philips licensed Russell's patents (then held by a Canadian company, Optical Recording Corp.) in the 1980s.[6][7][8]
The compact disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s.[9] Although originally dismissed by Philips Research management as a trivial pursuit,[10] the CD became the primary focus for Philips as the LaserDisc format struggled.[11] In 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980. After their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $1,000, over 400,000 CD players were sold in the United States between 1983 and 1984.[12] By 1988 CD sales in the United States surpassed those of vinyl LPs, and by 1992 CD sales surpassed those of prerecorded music cassette tapes.[13][14] The success of the compact disc has been credited to the cooperation between Philips and Sony, both of which came together to
"CD" redirects here. For other uses, see CD (disambiguation).
Compact disc (CD) is a digital optical disc data storage format released in 1982 and co-developed by Philips and Sony. The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. The first commercially available Audio CD player, the Sony CDP-101, was released October 1982 in Japan.
Compact Disc
The readable surface of a compact disc includes a spiral track wound tightly enough to cause light to diffract into a full visible spectrum
Media type Optical disc
Encoding Various
Capacity Typically up to 700 MiB (up to 80 minutes audio)
Read mechanism 780 nm wavelength (infrared and red edge) semiconductor laser, 1200 Kibit/s (1×)
Write mechanism 780 nm laser with a focused beam more powerful than one used for reading, 1200 Kibit/s (1×)
Standard Red Book
Developed by Philips, Sony
Usage Audio and data storage
Extended from LaserDisc
Extended to CD-RW
Standard CDs have a diameter of 120 millimetres (4.7 in) and can hold up to about 80 minutes of uncompressed audio or about 700 MiB of data. The Mini CD has various diameters ranging from 60 to 80 millimetres (2.4 to 3.1 in); they are sometimes used for CD singles, storing up to 24 minutes of audio, or delivering device drivers.
At the time of the technology's introduction in 1982, a CD could store much more data than a personal computer hard drive, which would typically hold 10 MB. By 2010, hard drives commonly offered as much storage space as a thousand CDs, while their prices had plummeted to commodity level. In 2004, worldwide sales of audio CDs, CD-ROMs and CD-Rs reached about 30 billion discs. By 2007, 200 billion CDs had been sold worldwide.[1]
From the early 2010s CDs were increasingly being replaced by other forms of digital storage and distribution, with the result that audio CD sales rates in the U.S. have dropped about 50% from their peak; however, they remain one of the primary distribution methods for the music industry.[2] In 2014, revenues from digital music services matched those from physical format sales for the first time.[3]
Contents
HistoryEdit
American inventor James T. Russell has been credited with inventing the first system to record digital information on an optical transparent foil that is lit from behind by a high-power halogen lamp.[4][5] Russell's patent application was first filed in 1966, and he was granted a patent in 1970. Following litigation, Sony and Philips licensed Russell's patents (then held by a Canadian company, Optical Recording Corp.) in the 1980s.[6][7][8]
The compact disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s.[9] Although originally dismissed by Philips Research management as a trivial pursuit,[10] the CD became the primary focus for Philips as the LaserDisc format struggled.[11] In 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. After a year of experimentation and discussion, the Red Book CD-DA standard was published in 1980. After their commercial release in 1982, compact discs and their players were extremely popular. Despite costing up to $1,000, over 400,000 CD players were sold in the United States between 1983 and 1984.[12] By 1988 CD sales in the United States surpassed those of vinyl LPs, and by 1992 CD sales surpassed those of prerecorded music cassette tapes.[13][14] The success of the compact disc has been credited to the cooperation between Philips and Sony, both of which came together to
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