A compact disc
Media type: Optical disc
Encoding: Various
Capacity: Typically up to 700 MB (up to 80 minutes audio)
Read mechanism: 780 nm wavelength (infrared and red edge) semiconductor laser, 1200 Kibit/s (1×)
Write mechanism1200 Kibit/s (1×)
UsageAudio and data storage
CD
Compact disc (CD) is a digital optical disc data storage format, 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), re writable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. Audio CD players have been commercially available since October 1982, when the first commercially available CD player was released in Japan.
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. An 80 min. CD-ROM holds 737,280,000 bytes -- roughly 737 MB(d), or about 703 MB(b) of data as a data CD. As an audio CD, however, this is 846,720,000 bytes -- roughly 847 MB(d), 803 MB(b). As long as you're talking about 842 MB(d) of AIFF files, that's an amount of audio data which should fit with a few MB to spare.
Creator of CD
The creator of CD was James Russel.
James T. Russell (born 1931 in
Bremerton, Washington) is an
American inventor. He earned a BA in
physics from Reed College in Portland
in 1953. He joined General Electric's
nearby labs in Richland, Washington, where he initiated many types of experimental instrumentation. He designed and built the first electron beam welder.
In 1965, Russell joined the Pacific Northwest National Laboratory of Battelle Memorial Institute in Richland. 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, and more than 1500 descriptive brochures were sent out to various interested parties.
Early optical recording technology, which forms the physical basis of videodisc, CD and DVD technology, was first published/filed by Dr. David Paul Gregg in 1958 and Philips researchers, Kramer and Compaan, in 1969. Russell's optical digital inventions were available publicly from 1970.
Comparison of several forms of disk storage showing tracks (not-to-scale); green denotes start and red denotes end.
The inventor of CD,
James Russel
Comparison of several forms of disk storage showing tracks (not-to-scale); green denotes start and red denotes end.
Comparison of several forms of disk storage showing tracks (not-to-scale); green denotes start and red denotes end.
Disc Storage
Disk storage is a general category of storage mechanisms where data are recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is a device implementing such a storage mechanism. Notable types are the hard disk drive(HDD) containing a non-removable disk, the floppy disk drive (FDD) and its removable floppy disk, and various optical disc drives and associated optical disc media. Optical drive is the general term for a CD drive, DVD drive and Bluray drive. Without an optical drive, you cannot use any of those discs.​ Notable types are the hard disk drive (HDD) containing a non-removable disk, the floppy disk drive (FDD) and its removable floppy disk, and various optical disc drives and associated optical disc media.
Audio information was originally recorded by analog methods . Similarly the first video disc used an analog recording method. In the music industry, analog recording has been mostly replaced by digital optical technology where the data are recorded in a digital format with optical information.
The first commercial digital disk storage device was the IBM 350 which shipped in 1956 as a part of the IBM 305 RAMAC computing system. The random-access, low-density storage of disks was developed to complement the already used sequential-access, high-density storage provided by tape drives using magnetic tape. Vigorous innovation in disk storage technology, coupled with less vigorous innovation in tape storage, has reduced the difference in acquisition cost per terabyte between disk storage and tape storage; however, the total cost of ownership of data on disk including power and management remains larger than that of tape.