Optical disc

optical mediaoptical data storageoptical discsdiscoptical diskdiscsopticalglass discsoptical disksCD/DVD
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc which encodes binary data (bits) in the form of pits (binary value of 0 or off, due to lack of reflection when read) and lands (binary value of 1 or on, due to a reflection when read) on a special material (often aluminium ) on one of its flat surfaces.wikipedia
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Optical disc recording technologies

optical disc recording technologyoverburnOverburning
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc which encodes binary data (bits) in the form of pits (binary value of 0 or off, due to lack of reflection when read) and lands (binary value of 1 or on, due to a reflection when read) on a special material (often aluminium ) on one of its flat surfaces.
Optical disc authoring requires a number of different optical disc recorder technologies working in tandem, from the optical disc media to the firmware to the control electronics of the optical disc drive.

Optical disc drive

optical driveCD driveDVD drive
The data is stored on the disc with a laser or stamping machine, and can be accessed when the data path is illuminated with a laser diode in an optical disc drive which spins the disc at speeds of about 200 to 4,000 RPM or more, depending on the drive type, disc format, and the distance of the read head from the center of the disc (inner tracks are read at a higher disc speed).
In computing, an optical disc drive (ODD) is a disc drive that uses laser light or electromagnetic waves within or near the visible light spectrum as part of the process of reading or writing data to or from optical discs.

Floppy disk

floppy disk drivefloppy drivediskette
Unlike the 31⁄2-inch floppy disk, most optical discs do not have an integrated protective casing and are therefore susceptible to data transfer problems due to scratches, fingerprints, and other environmental problems.
While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater capacity and transfer speeds, such as USB flash drives, flash storage cards, portable external hard disk drives, optical discs, and storage available through computer networks such as cloud storage.

CD-R

CDRrecordable CDCD-Rs
An optical disc is designed to support one of three recording types: read-only (e.g.: CD and CD-ROM), recordable (write-once, e.g. CD-R), or re-recordable (rewritable, e.g. CD-RW).
CD-R (Compact Disc-Recordable) is a digital optical disc storage format.

CD-RW

rewritable CDsCD-MOCDRW
An optical disc is designed to support one of three recording types: read-only (e.g.: CD and CD-ROM), recordable (write-once, e.g. CD-R), or re-recordable (rewritable, e.g. CD-RW).
CD-RW (Compact Disc-ReWritable) is a digital optical disc storage format introduced in 1997.

CD player

CD changerCD playersCompact Disc player
Optical discs are most commonly used for storing music (e.g. for use in a CD player), video (e.g. for use in a Blu-ray player), or data and programs for personal computers (PC).
A CD player is an electronic device that plays audio compact discs, which are a digital optical disc data storage format.

USB flash drive

flash driveUSB flash drivesUSB drive
For computer data backup and physical data transfer, optical discs such as CDs and DVDs are gradually being replaced with faster, smaller solid-state devices, especially the USB flash drive.
It is typically removable, rewritable and much smaller than an optical disc.

Optical media preservation

Libraries and archives enact optical media preservation procedures to ensure continued usability in the computer's optical disc drive or corresponding disc player.
The preservation of optical media is essential because it is a resource in libraries, and stores audio, video, and computer data to be accessed by patrons.

DVD

DVD-ROMDVDsDVD-9
It is of special interest that, filed 1989, issued 1990, generated royalty income for Pioneer Corporation's DVA until 2007 —then encompassing the CD, DVD, and Blu-ray systems.
DVD (an abbreviation of digital versatile disc) is a digital optical disc storage format invented and developed in 1995.

David Paul Gregg

Dr. David Paul Gregg
An early analog optical disc used for video recording was invented by David Paul Gregg in 1958 and patented in the US in 1961 and 1969.
He was the inventor of the optical disc (disk).

Bit

bitsbinary digitbinary digits
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc which encodes binary data (bits) in the form of pits (binary value of 0 or off, due to lack of reflection when read) and lands (binary value of 1 or on, due to a reflection when read) on a special material (often aluminium ) on one of its flat surfaces.
When relays were replaced by vacuum tubes, starting in the 1940s, computer builders experimented with a variety of storage methods, such as pressure pulses traveling down a mercury delay line, charges stored on the inside surface of a cathode-ray tube, or opaque spots printed on glass discs by photolithographic techniques.

Compact disc

CDCDsCD single
In computing and optical disc recording technologies, an optical disc (OD) is a flat, usually circular disc which encodes binary data (bits) in the form of pits (binary value of 0 or off, due to lack of reflection when read) and lands (binary value of 1 or on, due to a reflection when read) on a special material (often aluminium ) on one of its flat surfaces. In 1979, Philips and Sony, in consortium, successfully developed the audio compact disc.
Compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony and released in 1982.

LaserDisc

LDlaser discLaserVision
In 1975, Philips and MCA began to work together, and in 1978, commercially much too late, they presented their long-awaited Laserdisc in Atlanta. The LaserDisc format stored analog video signals for the distribution of home video, but commercially lost to the VHS videocassette format, due mainly to its high cost and non-re-recordability; other first-generation disc formats were designed only to store digital data and were not initially capable of use as a digital video medium.
LaserDisc (abbreviated as LD) is a home video format and the first commercial optical disc storage medium, initially licensed, sold and marketed as MCA DiscoVision in the United States in 1978.

HD DVD

HD-DVDhigh definition3× DVD
Blu-ray eventually prevailed in a high definition optical disc format war over a competing format, the HD DVD.
HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video.

High-definition optical disc format war

high definition optical disc format warformat waradvocates of the rival formats
Blu-ray eventually prevailed in a high definition optical disc format war over a competing format, the HD DVD.
The high-definition optical disc format war was between the Blu-ray and HD DVD optical disc standards for storing high-definition video and audio; it took place between 2006 and 2008 and was won by Blu-ray Disc.

AgInSbTe

Ag- and In- doped Sb 2 TeInAgTeSb
Rewritable discs typically contain an alloy recording layer composed of a phase change material, most often AgInSbTe, an alloy of silver, indium, antimony, and tellurium.
AgInSbTe, or Silver-Indium-Antimony-Tellurium, is a phase change material from the group of chalcogenide glasses, used in rewritable optical discs (such as rewritable CDs) and phase-change memory applications.

Video

analog videovideo albumvideo recording
The LaserDisc format stored analog video signals for the distribution of home video, but commercially lost to the VHS videocassette format, due mainly to its high cost and non-re-recordability; other first-generation disc formats were designed only to store digital data and were not initially capable of use as a digital video medium.
Analog and digital variants exist and can be carried on a variety of media, including radio broadcast, magnetic tape, optical discs, computer files, and network streaming.

Home video

home entertainmenthome mediavideo album
The LaserDisc format stored analog video signals for the distribution of home video, but commercially lost to the VHS videocassette format, due mainly to its high cost and non-re-recordability; other first-generation disc formats were designed only to store digital data and were not initially capable of use as a digital video medium.
The term originates from the VHS/Betamax era, when the predominant medium was videotape, but has carried over into optical disc formats like DVD and Blu-ray and, since the 2000s, into methods of digital distribution such as Netflix, Hulu, and Prime Video.

VHS

videoVHS tapeVHS tapes
The LaserDisc format stored analog video signals for the distribution of home video, but commercially lost to the VHS videocassette format, due mainly to its high cost and non-re-recordability; other first-generation disc formats were designed only to store digital data and were not initially capable of use as a digital video medium.
Optical disc formats later began to offer better quality than analog consumer video tape such as VHS and S-VHS.

Laser

laserslaser beamlaser light
The data is stored on the disc with a laser or stamping machine, and can be accessed when the data path is illuminated with a laser diode in an optical disc drive which spins the disc at speeds of about 200 to 4,000 RPM or more, depending on the drive type, disc format, and the distance of the read head from the center of the disc (inner tracks are read at a higher disc speed).

Sony

Sony CorporationSony ElectronicsSony Corp.
In 1979, Philips and Sony, in consortium, successfully developed the audio compact disc.
In 1986 they launched Write-Once optical discs (WO) and in 1988 launched Magneto-optical discs which were around 125MB size for the specific use of archival data storage.

GD-ROM

GD-ROM (an abbreviation of "Gigabyte Disc Read-Only Memory") is a proprietary optical disc format originally used for the Dreamcast video game console, as well as its arcade counterpart, the Sega NAOMI and select Triforce arcade board titles.

DualDisc

CD+DVDdual discDD
DualDisc was a type of double-sided optical disc product developed by a group of record companies including MJJ Productions Inc., EMI Music, Universal Music Group, Sony BMG Music Entertainment, Warner Music Group, and 5.1 Entertainment Group and later under the aegis of the Recording Industry Association of America (RIAA).

Constant linear velocity

CLVzoned constant linear velocitylinear velocity
Other factors that affect data storage density include: the existence of multiple layers of data on the disc, the method of rotation (Constant linear velocity (CLV), Constant angular velocity (CAV), or zoned-CAV), the composition of lands and pits, and how much margin is unused is at the center and the edge of the disc.
In optical storage, constant linear velocity (CLV) is a qualifier for the rated speed of an optical disc drive, and may also be applied to the writing speed of recordable discs.

Personal computer

PCPCspersonal computers
Optical discs are most commonly used for storing music (e.g. for use in a CD player), video (e.g. for use in a Blu-ray player), or data and programs for personal computers (PC).
Initially, the primary defining characteristic of netbooks was the lack of an optical disc drive, smaller size, and lower performance than full-size laptops.