Discs

A Compact Disc (or CD) is an optical disc used to store digital data, originally developed for storing digital audio. The CD, available on the market since late 1982, remains the standard playback medium for commercial audio recordings to the present day. more...

Home
Archery
Baseball & Softball
Basketball
Billiards
Bowling
Boxing
Canoes, Kayaks, Rafts
Climbing
Disc Golf
Accessories
Discs
Other
Equestrian
Football
Go-Karts, Recreational
Gymnastics
Ice Skating
Ice, Roller Hockey
Indoor Games
Inline, Roller Skating
Lacrosse
Martial Arts
Other Sports
Racquetball & Squash
Running
Scooters
Scuba, Snorkeling
Skateboarding
Snowmobiling
Soccer
Surfing, Wind Surfing
Swimming
Tennis
Triathlon
Wakeboarding, Waterskiing
Wholesale Lots

Standard CDs have a diameter of 120 mm and can hold up to 80 minutes of audio. There is also the Mini CD, with diameters ranging from 60 to 80 mm; they are sometimes used for CD singles, storing up to 24 minutes of audio.

The technology was later adapted and expanded to include data storage (CD-ROM), write-once audio and data storage (CD-R), rewritable media (CD-RW), SACD, VCD, SVCD, PhotoCD, PictureCD, CD-i, and Enhanced CD. CD-ROMs and CD-Rs remain widely used technologies in the computer industry. The CD and its extensions have been extremely successful: in 2004, worldwide sales of CD audio, CD-ROM, and CD-R reached about 30 billion discs. By 2007, 200 billion CDs had been sold worldwide.

History

The history of the compact disk can be traced as far back as 1965 when James Russell joined the Pacific Northwest National Laboratory of Battelle Memorial Institute in Richland, WA. There, in 1965, Russell invented the overall concept of optical digital recording and playback. The earliest patents by Russell, US 3,501,586, and 3,795,902 were filed in 1966, and 1969. respectively . He built prototypes, and the first was operating in 1973. In 1973, 1974, 1975 his prototype was viewed by about 100 companies, including Philips and Sony engineers.

Russell's optical digital inventions and development work preceded that at Philips by about 12 years, and were available publicly from 1970. It is fair to say that Russell's concepts, patents, prototypes, and literature instigated and in some measure guided the optical digital revolution.

The compact disc is a successful spin-off of the much less successful Laserdisc technology. In 1979, Sony and Philips Consumer Electronics set up a joint task force of engineers to design a new digital audio disc. The task force, led by prominent members Kees Immink and Toshitada Doi (土井利忠), progressed the research into laser technology and optical discs that had been started by Philips in 1977. After a year of experimentation and discussion, the taskforce produced the Red Book, the Compact Disc standard. Philips contributed the general manufacturing process, based on video LaserDisc technology. Philips also contributed Eight-to-Fourteen Modulation (EFM), which offers both a long playing time and a high resilience against disc defects such as scratches and fingerprints, while Sony contributed the error-correction method, CIRC. The Compact Disc Story, told by a former member of the taskforce, gives background information on the many technical decisions made, including the choice of the sampling frequency, playing time, and disc diameter. According to Philips, the Compact Disc was thus \"invented collectively by a large group of people working as a team.\"

Read more at Wikipedia.org