____ Is a Disk Drive That Uses Laser Light to Read From or Write to Optical Discs

Type of computer deejay storage dive

A CD-RW/DVD-ROM computer drive

The CD/DVD drive lens on an Acer laptop

Lenses from a Blu-ray writer in a Sony Vaio E series laptop

In computing, an optical disc drive (ODD) is a disc bulldoze that uses light amplification by stimulated emission of radiation light or electromagnetic waves within or about the visible light spectrum as part of the process of reading or writing information to or from optical discs. Some drives can but read from certain discs, but recent drives can both read and record, also called burners or writers (since they physically burn the organic dye on write-once CD-R, DVD-R and BD-R LTH discs). Compact discs, DVDs, and Blu-ray discs are mutual types of optical media which can be read and recorded past such drives.

Bulldoze types [edit]

As of 2021^[update], most of the optical disc drives on the market place are DVD-ROM drives and BD-ROM drives which read and record from those formats, forth with having backward compatibility with CD, CD-R and CD-ROM discs; meaty disc drives are no longer manufactured exterior of audio devices. Read-only DVD and Blu-ray drives are likewise manufactured, only are less usually establish in the consumer market and mainly express to media devices such equally game consoles and disc media players. Over the last ten years, laptop computers no longer come with optical disc drives in social club to reduce costs and make devices lighter, requiring consumers to buy external optical drives.

Appliances and functionality [edit]

Optical disc drives are an integral function of standalone appliances such as CD players, DVD players, Blu-ray Disc players, DVD recorders, sure desktop video game consoles, such as Sony PlayStation four, Microsoft Xbox One, Nintendo Wii U, Sony PlayStation 5 and Xbox Series X and also in older consoles, such as the Sony PlayStation 3 and Xbox 360, and sure portable video game consoles, such as Sony PlayStation Portable (using proprietary now discontinued UMDs). They are also very commonly used in computers to read software and media distributed on disc and to tape discs for archival and information commutation purposes. Floppy deejay drives, with capacity of i.44 MB, take been fabricated obsolete: optical media are cheap and have vastly college capacity to handle the big files used since the days of floppy discs, and the vast majority of computers and much consumer amusement hardware have optical writers. USB flash drives, high-capacity, small, and cheap, are suitable where read/write capability is required.

Disc recording is restricted to storing files playable on consumer appliances (films, music, etc.), relatively small volumes of data (east.g. a standard DVD holds 4.7 gigabytes, however, higher-capacity formats such as multi-layer Blu-ray Discs exist) for local employ, and data for distribution, but simply on a small-scale calibration; mass-producing large numbers of identical discs by pressing (replication) is cheaper and faster than individual recording (duplication).

Optical discs are used to back up relatively pocket-sized volumes of data, but bankroll upwardly of unabridged hard drives, which as of 2015^[update] typically contain many hundreds of gigabytes or even multiple terabytes, is less applied. Large backups are frequently instead made on external difficult drives, as their price has dropped to a level making this viable; in professional person environments magnetic tape drives are likewise used.

Some optical drives also permit predictively scanning the surface of discs for errors and detecting poor recording quality.^{[1] [2]}

With an choice in the optical disc authoring software, optical disc writers are able to simulate the writing process on CD-R, CD-RW, DVD-R and DVD-RW, which allows for testing such as observing the writing speeds and patterns (due east.g. constant athwart velocity, constant linear velocity and P-CAV and Z-CLV variants) with different writing speed settings and testing the highest capacity of an private disc that would be achievable using overburning, without writing any data to the disc.^[three]

Few optical drives allow simulating a FAT32 flash drive from optical discs containing ISO9660/Joliet and UDF file systems or audio tracks (simulated as .wav files),^[4] for compatibility with most USB multimedia appliances.^[5]

Key components [edit]

Form factors [edit]

Optical drives for computers come in two main course factors: half-height (also known equally desktop drive) and slim type (used in laptop computers and compact desktop computers). They exist equally both internal and external variants.

Half-height optical drives are around 4 centimetres tall, while slim blazon optical drives are around one cm tall.

One-half-height optical drives operate upwards of twice the speeds every bit slim type optical drives, considering speeds on slim type optical drives are constrained to the physical limitations of the drive motor's rotation speed (around 5000rpm^[six]) rather than the performance of the optical pickup system.

Considering half-tiptop demand much more than electrical ability and a voltage of 12 V DC, while slim optical drives run on five volts, external half height optical drives require split external ability input, while external slim type are normally able to operate entirely on ability delivered through a reckoner'due south USB port. Half height drives are likewise faster than Slim drives due to this, since more power is required to spin the disc at higher speeds.

Half-height optical drives hold discs in place from both sides while slim type optical drives fasten the disc from the bottom.

One-half height drives fasten the disc using ii spindles containing a magnet each, one under and one above the disc tray. The spindles may exist lined with flocking or a texturized silicone material to exert friction on the disc, to keep it from slipping. The upper spindle is left slightly loose and is attracted to the lower spindle because of the magnets they take. When the tray is opened, a mechanism driven past the motility of the tray pulls the lower spindle away from the upper spindle and vice versa when the tray is closed. When the tray is closed, the lower spindle touches the inner circumference of the disc, and slightly raises the disc from the tray to the upper spindle, which is attracted to the magnet on the lower disc, clamping the disc in place. Only the lower spindle is motorized. Trays in one-half elevation drives often fully open and close using a motorized machinery that can be pushed to close, controlled by the computer, or controlled using a button on the drive. Trays on half height and slim drives tin can also be locked past whatever program is using it, yet information technology tin still exist ejected past inserting the terminate of a paper clip into an emergency eject hole on the front of the drive. Early CD players such every bit the Sony CDP-101 used a split up motorized mechanism to clamp the disc to the motorized spindle.

Slim drives apply a special spindle with spring loaded peculiarly shaped studs that radiate outwards, pressing confronting the inner border of the disc. The user has to put compatible pressure onto the inner circumference of the disc to clench it to the spindle and pull from the outer circumference while placing the thumb on the spindle to remove the disc, flexing information technology slightly in the process and returning to its normal shape subsequently removal. The outer rim of the spindle may have a texturized silicone surface to exert friction keeping the disc from slipping. In slim drives most if not all components are on the disc tray, which pops out using a leap mechanism that can be controlled past the computer. These trays cannot shut on their own; they have to be pushed until the tray reaches a terminate. ^[seven]

Laser and eyes [edit]

Optical pickup arrangement [edit]

The almost important part of an optical disc drive is an optical path, which is within a pickup head (PUH). The PUH is besides known as a laser pickup, optical pickup, pickup, pickup assembly, laser assembly, laser optical assembly, optical pickup head/unit or optical associates.^[8] Information technology commonly consists of a semiconductor light amplification by stimulated emission of radiation diode, a lens for focusing the light amplification by stimulated emission of radiation beam, and photodiodes for detecting the low-cal reflected from the disc's surface.^[9]

Initially, CD-blazon lasers with a wavelength of 780 nm (within the infrared) were used. For DVDs, the wavelength was reduced to 650 nm (red color), and for Blu-ray Disc this was reduced even farther to 405 nm (violet color).

Ii master servomechanisms are used, the first to maintain the proper distance between lens and disc, to ensure the laser beam is focused as a pocket-sized laser spot on the disc. The second servo moves the pickup head along the disc's radius, keeping the beam on the track, a continuous spiral data path. Optical disc media are 'read' outset at the inner radius to the outer edge.

Nigh the laser lens, optical drives are usually equipped with 1 to iii tiny potentiometers (usually separate ones for CDs, DVDs, and usually a third one for Blu-ray Discs if supported past the drive^[10]) that tin can be turned using a fine screwdriver. The potentiometer is in a serial circuit with the laser lens and can be used to manually increase and decrease the light amplification by stimulated emission of radiation ability for repair purposes.^{[xi] [12] [13] [14] [15] [16]}

The laser diode used in DVD writers can take powers of up to 100 milliwatts, such high powers are used during writing.^[17] Some CD players have automatic gain control (AGC) to vary the power of the laser to ensure reliable playback of CD-RW discs.^{[eighteen] [19]}

Readability (the ability to read physically damaged or soiled discs) may vary among optical drives due to differences in optical pickup systems, firmwares, and damage patterns.^[twenty]

Read-only media [edit]

The optical sensor out of a CD/DVD bulldoze. The two larger rectangles are the photodiodes for pits, the inner i for land. This one also includes amplification and pocket-sized processing.

On factory-pressed read only media (ROM), during the manufacturing process the tracks are formed by pressing a thermoplastic resin into a nickel stamper that was made by plating a glass 'master' with raised 'bumps' on a apartment surface, thus creating pits and lands in the plastic disk. Because the depth of the pits is approximately 1-quarter to one-sixth of the laser's wavelength, the reflected beam's phase is shifted in relation to the incoming axle, causing mutual subversive interference and reducing the reflected beam's intensity. This is detected by photodiodes that create corresponding electric signals.

Recordable media [edit]

This department is missing information about laser wattages for reading and writing of individual media types. Please expand the section to include this data. Farther details may exist on the talk page. (Baronial 2020)

An optical disk recorder encodes (also known as burning, since the dye layer is permanently burned) data onto a recordable CD-R, DVD-R, DVD+R, or BD-R disc (called a blank) by selectively heating (burning) parts of an organic dye layer with a laser.^{[ citation needed ]}

This changes the reflectivity of the dye, thereby creating marks that can be read like the pits and lands on pressed discs. For recordable discs, the process is permanent and the media can be written to only once. While the reading laser is usually not stronger than five mW, the writing light amplification by stimulated emission of radiation is considerably more powerful.^[21] DVD lasers operate at voltages of around two.5 volts.^[22]

The higher the writing speed, the less time a laser has to rut a point on the media, thus its ability has to increase proportionally. DVD burners' lasers often top at about 200 mW, either in continuous wave and pulses, although some accept been driven up to 400 mW before the diode fails.

Rewriteable media [edit]

For rewritable CD-RW, DVD-RW, DVD+RW, DVD-RAM, or BD-RE media, the laser is used to melt a crystalline metal alloy in the recording layer of the disc. Depending on the amount of power practical, the substance may exist allowed to melt back (modify the stage back) into crystalline form or left in an baggy grade, enabling marks of varying reflectivity to be created.

Double-sided media [edit]

Double-sided media may be used, simply they are not easily accessed with a standard drive, as they must exist physically turned over to access the data on the other side.

Dual layer media [edit]

Double layer or dual layer (DL) media have two independent data layers separated past a semi-cogitating layer. Both layers are attainable from the same side, simply require the optics to change the laser'south focus. Traditional single layer (SL) writable media are produced with a spiral groove molded in the protective polycarbonate layer (not in the information recording layer), to lead and synchronize the speed of recording head. Double-layered writable media have: a get-go polycarbonate layer with a (shallow) groove, a showtime information layer, a semi-reflective layer, a second (spacer) polycarbonate layer with some other (deep) groove, and a second data layer. The first groove spiral usually starts on the inner border and extends outwards, while the second groove start on the outer border and extends in.^{[23] [24]}

Photothermal printing [edit]

Some drives support Hewlett-Packard'due south LightScribe, or the culling LabelFlash photothermal printing technology for labeling specially coated discs.

Multi beam drives [edit]

Zen Technology and Sony accept developed drives that use several laser beams simultaneously to read discs and write to them at higher speeds than what would be possible with a single laser beam. The limitation with a single laser axle comes from wobbling of the disc that may occur at high rotational speeds; at 25,000 RPMs CDs become unreadable^[18] while Blu-rays cannot be written to beyond 5,000 RPMs.^[25] With a unmarried laser axle, the just way to increase read and write speeds without reducing the pit length of the disc (which would allow for more pits and thus bits of data per revolution, just may require smaller wavelength light) is by increasing the rotational speed of the disc which reads more than pits in less fourth dimension, increasing data rate; hence why faster drives spin the disc at higher speeds. In addition, CDs at 27,500 RPMs (such as to read the within of a CD at 52x) may explode causing all-encompassing damage to the disc's surround, and poor quality or damaged discs may explode at lower speeds.^{[26] [eighteen]}

In Zen'southward organisation (adult in conjunction with Sanyo and licensed by Kenwood), a diffraction grating is used to split a laser beam into 7 beams, which are and then focused into the disc; a fundamental beam is used for focusing and tracking the groove of the disc leaving 6 remaining beams (3 on either side) that are spaced evenly to read 6 separate portions of the groove of the disc in parallel, effectively increasing read speeds at lower RPMs, reducing bulldoze noise and stress on the disc. The beams then reflect back from the disc, and are collimated and projected into a special photodiode array to be read. The commencement drives using the technology could read at 40x, later on increasing to 52x and finally 72x. It uses a single optical pickup.^{[27] [28] [29] [30] [31] [32]}

In Sony'due south system (used on their proprietary Optical Disc Archive system which is based on Archival Disc, itself based on Blu-ray) the bulldoze has 4 optical pickups, two on each side of the disc, with each pickup having two lenses for a total of 8 lenses and laser beams. This allows for both sides of the disc to be read and written to at the same fourth dimension, and for the contents of the disc to exist verified during writing.^[33]

Rotational machinery [edit]

• 

  Comparison of several forms of disk storage showing tracks (non-to-scale); green denotes kickoff and red denotes end.
  * Some CD-R(Westward) and DVD-R(W)/DVD+R(W) recorders operate in ZCLV, CAA or CAV modes.

The rotational mechanism in an optical drive differs considerably from that of a hard disk drive bulldoze's, in that the latter keeps a constant angular velocity (CAV), in other words a constant number of revolutions per minute (RPM). With CAV, a college throughput is generally achievable at the outer disc compared to the inner.

On the other hand, optical drives were adult with an assumption of achieving a constant throughput, in CD drives initially equal to 150 KiB/due south. It was a feature important for streaming audio information that ever tend to require a constant flake charge per unit. But to ensure no disc chapters was wasted, a head had to transfer data at a maximum linear rate at all times also, without slowing on the outer rim of the disc. This led to optical drives—until recently—operating with a constant linear velocity (CLV). The spiral groove of the disc passed under its caput at a constant speed. The implication of CLV, equally opposed to CAV, is that disc angular velocity is no longer constant, and the spindle motor needed to exist designed to vary its speed from between 200 RPM on the outer rim and 500 RPM on the inner, keeping the information rate abiding.

Later CD drives kept the CLV paradigm, but evolved to achieve higher rotational speeds, popularly described in multiples of a base speed. As a event, a 4× CLV drive, for example, would rotate at 800-2000 RPM, while transferring data steadily at 600 KiB/southward, which is equal to four × 150 KiB/s.

For DVDs, base or i× speed is ane.385 MB/due south, equal to 1.32 MiB/s, approximately 9 times faster than the CD base speed. For Blu-ray drives, base of operations speed is half dozen.74 MB/s, equal to vi.43 MiB/s.

The Z-CLV recording blueprint is easily visible afterward burning a DVD-R.

Because keeping a abiding transfer rate for the whole disc is not so important in near contemporary CD uses, a pure CLV approach had to be abandoned to go along the rotational speed of the disc safely depression while maximizing data charge per unit. Some drives work in a fractional CLV (PCLV) scheme, by switching from CLV to CAV only when a rotational limit is reached. Only switching to CAV requires considerable changes in hardware design, so instead most drives apply the zoned constant linear velocity (Z-CLV) scheme. This divides the disc into several zones, each having its own constant linear velocity. A Z-CLV recorder rated at "52×", for example, would write at 20× on the innermost zone and and then progressively increment the speed in several detached steps up to 52× at the outer rim. Without higher rotational speeds, increased read performance may exist attainable by simultaneously reading more than ane betoken of a data groove, also known as multi-beam,^[34] but drives with such mechanisms are more expensive, less compatible, and very uncommon.

Limit [edit]

Both DVDs and CDs have been known to explode^[35] when damaged or spun at excessive speeds. This imposes a constraint on the maximum rubber speeds (56× CAV for CDs or around 18×CAV in the case of DVDs) at which drives can operate.

The reading speeds of most one-half-height optical disc drives released since circa 2007 are limited to ×48 for CDs, ×xvi for DVDs and ×12 (angular velocities) for Blu-ray Discs.^[a] Writing speeds on selected write-once media are higher.^{[seven] [36] [37]}

Some optical drives additionally throttle the reading speed based on the contents of optical discs, such as max. 40× CAV (abiding angular velocity) for the Digital Audio Extraction ("DAE") of Sound CD tracks,^[36] xvi× CAV for Video CD contents^[37] and even lower limitations on before models such as 4× CLV (abiding linear velocity) for Video CDs.^{[38] [39]}

Loading mechanisms [edit]

Tray and slot loading [edit]

Electric current optical drives utilize either a tray-loading mechanism, where the disc is loaded onto a motorized (as utilized by half-summit, "desktop" drives) tray, a manually operated tray (as utilized in laptop computers, also called slim type), or a slot-loading mechanism, where the disc is slid into a slot and drawn in past motorized rollers. Slot-loading optical drives be in both half-acme (desktop) and slim type (laptop) form factors.^[7]

With both types of mechanisms, if a CD or DVD is left in the drive after the computer is turned off, the disc cannot be ejected using the normal eject mechanism of the drive. However, tray-loading drives account for this state of affairs past providing a small hole where i can insert a paperclip to manually open up the bulldoze tray to retrieve the disc.^[40]

Slot-loading optical disc drives are prominently used in game consoles and vehicle audio units. Although allowing more than convenient insertion, those have the disadvantages that they cannot usually accept the smaller 80 mm diameter discs (unless 80 mm optical disc adapter is used) or any non-standard sizes, normally have no emergency eject pigsty or eject button, and therefore have to be disassembled if the optical disc cannot exist ejected ordinarily. Notwithstanding, some slot-loading optical drives have been engineered to support miniature discs. The Nintendo Wii, considering of backward compatibility with Nintendo GameCube games,^{[41] [42]} and PlayStation 3^[43] video game consoles are able to load both standard size DVDs and 80 mm discs in the same slot-loading drive. Its successor's slot drive however, the Wii U, lacks miniature disc compatibility.^[44]

At that place were also some early CD-ROM drives for desktop PCs in which its tray-loading mechanism will eject slightly and user has to pull out the tray manually to load a CD^{[ citation needed ]}, similar to the tray ejecting method used in internal optical disc drives of mod laptops and modern external slim portable optical disc drives. Like the peak-loading machinery, they have spring-loaded brawl bearings on the spindle.

Top-load [edit]

A small number of drive models, mostly compact portable units, have a top-loading machinery where the drive lid is manually opened up and the disc is placed straight onto the spindle^{[45] [46]} (for example, all PlayStation One consoles, PlayStation 2 Slim, PlayStation 3 Super Slim, Nintendo GameCube consoles, most portable CD players, and some standalone CD recorders feature top-loading drives). These sometimes have the advantage of using spring-loaded ball bearings to concur the disc in place, minimizing damage to the disc if the drive is moved while it is spun upwardly.

Unlike tray and slot loading mechanisms by default, summit-load optical drives tin can be opened without beingness connected to power.

Cartridge load [edit]

Some early CD-ROM drives used a mechanism where CDs had to be inserted into special cartridges or caddies, somewhat similar in appearance to a 3.5 inch micro floppy diskette. This was intended to protect the disc from accidental damage by enclosing it in a tougher plastic casing, but did non gain broad acceptance due to the additional cost and compatibility concerns—such drives would besides inconveniently require "bare" discs to exist manually inserted into an openable caddy before use. Ultra Density Optical (UDO), Magneto-optical drives, Universal Media Disc (UMD), DataPlay, Professional Disc, MiniDisc, Optical Disc Archive likewise every bit early DVD-RAM and Blu-ray discs use optical disc cartridges.

Computer interfaces [edit]

All optical disc-drives use the SCSI-protocol on a control omnibus level, and initial systems used either a fully featured SCSI bus or as these were some what cost-prohibitive to sell to consumer applications, a proprietary cost-reduced version of the bus. This is because conventional ATA-standards at the time did not support, or have whatever provisions for whatsoever sort of removable media or hot-plugging of deejay drives. About modern internal drives for personal computers, servers, and workstations are designed to fit in a standard five+ 1⁄4 -inch (besides written equally v.25 inch) drive bay and connect to their host via an ATA or SATA bus interface, only communicate using the SCSI protocol commands on software level as per the ATA Package Interface standard adult for making Parallel ATA/IDE interfaces compatible with removable media. Some devices may back up vendor-specific commands such every bit recording density ("GigaRec"), laser power setting ("VariRec"), ability to manually difficult-limit rotation speed in a way that overrides the universal speed setting (separately for reading and writing), and adjusting the lens and tray motility speeds where a lower setting reduces noise, as implmenented on some Plextor drives, besides as the ability to strength overspeed burning, significant across speed recommended for the media blazon, for testing purposes, as implemented on some Lite-ON drives.^{[47] [48] [49] [50]} Additionally, there may be digital and analog outputs for sound. The outputs may be connected via a header cablevision to the audio card or the motherboard or to headphones or an external speaker with a 3.5mm AUX plug cable that many early optical drives are equipped with.^{[51] [52]} At one time, computer software resembling CD players controlled playback of the CD.^{[53] [54]} Today the data is extracted from the disc as digital data, to be played back or converted to other file formats.

Some early optical drives accept dedicated buttons for CD playback controls on their front end panel, allowing them to deed equally a standalone compact disc player.^[51]

External drives were popular in the offset, because the drives frequently required complex electronics to institute, rivaling in complexity the Host computer system itself. External drives using SCSI, Parallel port, USB and FireWire interfaces exist, virtually mod drives existence USB. Some portable versions for laptops ability themselves from batteries or directly from their interface motorbus.

Drives with a SCSI interface were originally the just arrangement interface available, only they never became pop in the price sensitive low-end consumer market which constituted majority of the demand. They were less common and tended to be more than expensive, considering of the cost of their interface chipsets, more complex SCSI connectors, and small volume of sales in comparison to proprietary cost-reduced applications, only virtually chiefly considering most consumer market computer systems did non have any sort of SCSI interface in them the market for them was small. However, back up for multitude of various cost-reduced proprietary optical bulldoze bus standards were ordinarily embedded with sound cards which were frequently bundled with the optical drives themselves in the early years. Some sound card and optical drive bundles even featured a full SCSI bus. Modern IDE/ATAPI compliant Parallel ATA and Serial ATA bulldoze control chipsets and their interface engineering science is more complex to manufacture than a traditional 8bit 50Mhz SCSI drive interface, because they characteristic properties of both the SCSI and ATA bus, just are cheaper to make overall due to economies of scale.

When the optical disc bulldoze was first developed, it was not easy to add to calculator systems. Some computers such as the IBM PS/2 were standardizing on the iii+ 1⁄2 -inch floppy and 3+ 1⁄2 -inch hd and did non include a place for a big internal device. Also IBM PCs and clones at commencement only included a unmarried (parallel) ATA drive interface, which by the time the CD-ROM was introduced, was already being used to support two hard drives and were completely incapable of supporting removable media, a drive falling off or being removed from the bus while the system was alive, would cause an unrecoverable error and crash the entire arrangement. Early on consumer grade laptops simply had no born high-speed interface for supporting an external storage device. High-end workstation systems and laptops featured a SCSI interface which had a standard for externally connected devices.

HP C4381A CD-Writer Plus 7200 Serial, showing parallel ports to connect between a printer and the computer

This was solved through several techniques:

• Early audio cards could include a CD-ROM drive interface. Initially, such interfaces were proprietary to each CD-ROM manufacturer. A sound bill of fare could often have 2 or three different interfaces which are able to communicate with the CD-ROM drive.
• A method for using the parallel port to use with external drives was developed at some point. This interface was traditionally used to connect a printer, simply despite popular myth it is not its just use and various different external auxiliary devices exist for the IEEE-1278 bus, including but not limited to record backup drives etc. This was wearisome merely an choice for low-to-midrange laptops with out integrated or PCMCIA extension omnibus continued SCSI.
• A PCMCIA optical bulldoze interface was also adult for laptops.
• A SCSI card could be installed in desktop PCs to cater for an external SCSI bulldoze enclosure or to run internally mounted SCSI Hard disk drive drives and optical drives, though SCSI was typically somewhat more expensive than other options, with some OEMs charging a premium for it.

Due to lack of asynchrony in existing implementations, an optical bulldoze encountering damaged sectors may cause estimator programs trying to admission the drives, such equally Windows Explorer, to lock up.

Internal mechanism of a drive [edit]

Internal machinery of a DVD-ROM Drive. Run into text for details.

The optical drives in the photos are shown correct side up; the disc would sit on summit of them. The laser and optical organization scans the underside of the disc.

With reference to the top photograph, just to the correct of epitome centre is the disc motor, a metal cylinder, with a grey centering hub and black safety drive ring on top. In that location is a disc-shaped round clamp, loosely held inside the embrace and free to rotate; it's not in the photo. After the disc tray stops moving inward, as the motor and its attached parts rise, a magnet about the top of the rotating associates contacts and strongly attracts the clench to agree and center the disc. This motor is an "outrunner"-style brushless DC motor which has an external rotor – every visible role of it spins.

Ii parallel guide rods that run betwixt upper left and lower right in the photograph comport the "sled", the moving optical read-write head. Equally shown, this "sled" is close to, or at the position where it reads or writes at the border of the disc. To move the "sled" during continuous read or write operations, a stepper motor rotates a leadscrew to motility the "sled" throughout its total travel range. The motor, itself, is the short gray cylinder just to the left of the most-distant shock mount; its shaft is parallel to the support rods. The leadscrew is the rod with evenly-spaced darker details; these are the helical grooves that engage a pin on the "sled".

In contrast, the mechanism shown in the second photo, which comes from a cheaply made DVD player, uses less accurate and less efficient brushed DC motors to both movement the sled and spin the disc. Some older drives utilize a DC motor to motion the sled, but as well take a magnetic rotary encoder to keep runway of the position. Well-nigh drives in computers use stepper motors.

The grayness metal chassis is stupor-mounted at its 4 corners to reduce sensitivity to external shocks, and to reduce bulldoze racket from residual imbalance when running fast. The soft shock mount grommets are just below the contumely-colored screws at the four corners (the left one is obscured).

In the tertiary photo, the components nether the embrace of the lens mechanism are visible. The two permanent magnets on either side of the lens holder as well as the coils that move the lens can be seen. This allows the lens to exist moved up, down, forward, and backwards to stabilize the focus of the axle.

In the fourth photo, the inside of the optics package tin can be seen. Annotation that since this is a CD-ROM bulldoze, there is merely one light amplification by stimulated emission of radiation, which is the black component mounted to the bottom left of the associates. Just above the laser are the beginning focusing lens and prism that direct the beam at the disc. The alpine, sparse object in the centre is a half-silvered mirror that splits the laser beam in multiple directions. To the bottom correct of the mirror is the main photodiode that senses the beam reflected off the disc. Higher up the main photodiode is a second photodiode that is used to sense and regulate the ability of the laser.

The irregular orange fabric is flexible etched copper foil supported by thin sail plastic; these are "flexible circuits" that connect everything to the electronics (which is not shown).

History [edit]

The kickoff laser disc, demonstrated in 1972, was the Laservision 12-inch video disc. The video betoken was stored as an analog format similar a video cassette. The first digitally recorded optical disc was a v-inch sound meaty disc (CD) in a read-only format created by Sony and Philips in 1975.^[55]

The kickoff erasable optical disc drives were announced in 1983, by Matsushita (Panasonic),^[56] Sony, and Kokusai Denshin Denwa (KDDI).^[57] Sony eventually released the first commercial erasable and rewritable five+ 1⁄4 -inch optical disc drive in 1987,^[55] with dual-sided discs capable of holding 325 MB per side.^[56]

The CD-ROM format was adult by Sony and Denon, introduced in 1984, as an extension of Meaty Disc Digital Sound and adapted to hold any form of digital data. The CD-ROM format has a storage chapters of 650 MB. Also in 1984, Sony introduced a LaserDisc data storage format, with a larger data chapters of 3.28 GB.^[58]

In September 1992, Sony announced the MiniDisc format, which was supposed to combine the sound clarity of CD'south and the convenience of a cassette size.^[59] The standard capacity holds lxxx minutes of audio. In January 2004, Sony revealed an upgraded Hi-Md format, which increased the chapters to 1 GB (48 hours of audio).

The DVD format, developed past Panasonic, Sony, and Toshiba, was released in 1995, and was capable of property iv.7 GB per layer; with the first DVD players shipping on Nov 1, 1996, past Panasonic and Toshiba in Japan and the first DVD-ROM compatible computers being shipped on November 6 of that yr by Fujitsu.^[60] Sales of DVD-ROM drives for computers in the U.S. began on March 24, 1997, when Creative Labs released their PC-DVD kit to the marketplace.^[61]

In 1999, Kenwood released a multi-axle optical bulldoze that achieved burning speeds every bit loftier equally 72×, which would require dangerous spinning speeds to attain with single-axle burning.^{[27] [62]} However, it suffered from reliability issues.^[29]

The kickoff Blu-ray prototype was unveiled by Sony in Oct 2000,^[63] and the first commercial recording device was released to marketplace on April 10, 2003.^[64] In January 2005, TDK announced that they had developed an ultra-difficult yet very sparse polymer coating ("Durabis") for Blu-ray Discs; this was a meaning technical advance because better protection was desired for the consumer market to protect bare discs against scratching and damage compared to DVD. Technically Blu-ray Disc also required a thinner layer for the narrower axle and shorter wavelength 'blue' laser.^[65] The first BD-ROM players (Samsung BD-P1000) were shipped in mid-June 2006.^[66] The get-go Blu-ray Disc titles were released by Sony and MGM on June 20, 2006.^[67] The commencement mass-marketplace Blu-ray Disc rewritable bulldoze for the PC was the BWU-100A, released past Sony on July 18, 2006.^[68]

Starting in the mid 2010s, calculator manufacturers began to end including built-in optical disc drives on their products, with the advent of inexpensive, rugged (scratches tin not crusade corrupted data, inaccessible files or skipping audio/video), fast and high chapters USB drives and video on demand over the internet. Excluding an optical bulldoze allows for circuit boards in laptops to exist larger and less dense, requiring less layers, reducing production costs while also reducing weight and thickness, or for batteries to be larger. Computer instance manufacturers as well began to stop including 5+ ane⁄4 -inch bays for installing optical disc drives. However, new optical disc drives are still (as of 2020) available for purchase. Notable optical disc drive OEMs include Hitachi, LG Electronics (merged into Hitachi-LG Data Storage), Toshiba, Samsung Electronics (merged into Toshiba Samsung Storage Engineering science), Sony, NEC (merged into Optiarc), Lite-On, Philips (merged into Philips & Lite-On Digital Solutions), Pioneer Corporation, Plextor, Panasonic, Yamaha Corporation and Kenwood.^[69]

Compatibility [edit]

Most optical drives are backward compatible with their ancestors upwards to CD, although this is not required past standards.

Compared to a CD'southward 1.2 mm layer of polycarbonate, a DVD'southward laser beam only has to penetrate 0.half-dozen mm in order to reach the recording surface. This allows a DVD drive to focus the beam on a smaller spot size and to read smaller pits. DVD lens supports a different focus for CD or DVD media with same laser. With the newer Blu-ray Disc drives, the laser only has to penetrate 0.ane mm of material. Thus the optical assembly would normally have to have an even greater focus range. In practice, the Blu-ray optical system is split from the DVD/CD system.

Optical disc bulldoze	Optical disc or optical media
	Pressed CD	CD-R	CD-RW	Pressed DVD	DVD-R	DVD+R	DVD-RW	DVD+RW	DVD+R DL	Pressed CAT BD	BD-R	BD-RE	BD-R DL	BD-RE DL	BD-R XL	BD-RE XL
Audio CD player	Read	Read 1	Read ii12	None	None	None	None	None	None	None	None	None	None	None	None	None
CD-ROM drive	Read	Read ane	Read 2	None	None	None	None	None	None	None	None	None	None	None	None	None
CD-R recorder	Read	Write	Read	None	None	None	None	None	None	None	None	None	None	None	None	None
CD-RW recorder	Read	Write	Write	None	None	None	None	None	None	None	None	None	None	None	None	None
DVD-ROM drive	Read	Read 3	Read 3	Read	Read 4	Read 4	Read four	Read 4	Read 5	None	None	None	None	None	None	None
DVD-R recorder	Read	Write	Write	Read	Write	Read 6	Read	Read 6	Read v	None	None	None	None	None	None	None
DVD-RW recorder	Read	Write	Write	Read	Write	Read 7	Write 8	Read vi	Read 5	None	None	None	None	None	None	None
DVD+RW recorder	Read	Write	Write	Read	Read 6	Read 9	Read 6	Write	Read five	None	None	None	None	None	None	None
DVD+R recorder	Read	Write	Write	Read	Read six	Write	Read 6	Write	Read 5	None	None	None	None	None	None	None
DVD±RW recorder	Read	Write	Write	Read	Write	Write	Write	Write	Read five	None	None	None	None	None	None	None
DVD±RW/DVD+R DL recorder13	Read	Write	Write	Read	Write 10	Write	Write 10	Write	Write	None	None	None	None	None	None	None
BD-ROM	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	None	None
BD-R recorder	Read xi	Write 11	Write 11	Read	Write	Write	Write	Write	Write	Read	Write	Read	Read	Read	None	None
BD-RE recorder	Read 11	Write 11	Write 11	Read	Write	Write	Write	Write	Write	Read	Write	Write	Read	Read	None	None
BD-R DL recorder	Read 11	Write eleven	Write 11	Read	Write	Write	Write	Write	Write	Read	Write	Write	Write	Read	None	None
BD-RE DL recorder	Read xi	Write 11	Write eleven	Read	Write	Write	Write	Write	Write	Read	Write	Write	Write	Write	None	None
BD-ROM Twoscore	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read	Read
BD-R Twoscore recorder	Read 11	Write 11	Write 11	Read	Write	Write	Write	Write	Write	Read	Write	Write	Write	Write	Write	Read
BD-RE Xl recorder	Read xi	Write xi	Write 11	Read	Write	Write	Write	Write	Write	Read	Write	Write	Write	Write	Write	Write

• ^1 Some types of CD-R media with less-reflective dyes may cause problems.
• ^ii May not work in not MultiRead-compliant drives.
• ^3 May not work in some early-model DVD-ROM drives. CD-R would not work in whatever drive that did non have a 780 nm laser. CD-RW compatibility varied.^[70]
• ^iv DVD+RW discs did not work in early video players that played DVD-RW discs. This was not due to whatsoever incompatibility with the format only was a deliberate feature built into the firmware by ane^{[ which? ]} drive manufacturer.
• ^5 Read compatibility with existing DVD drives may vary greatly with the brand of DVD+R DL media used. Besides drives that predated the media did non take the book code for DVD+R DL media in their firmware (this was non an issue for DVD-R DL though some drives could simply read the beginning layer).
• ^six Early DVD+RW and DVD+R recorders could not write to DVD-R(W) media (and vice versa).
• ^7 Volition work in all drives that read DVD-R as compatibility ID byte is the same.
• ^8 Recorder firmware may blacklist or otherwise decline to record to some brands of DVD-RW media.
• ^ix DVD+RW format was released earlier DVD+R. All DVD+RW only drives could be upgraded to write DVD+R discs by a firmware upgrade.
• ^10 As of Apr 2005, all DVD+R DL recorders on the market are Super Multi-capable.
• ^xi Equally of Oct 2006, recently released BD drives are able to read and write CD media.
• ^12 Older CD actor models might struggle with the low reflectivity of CD-RW media.
• ^13 Also known as "DVD Multi Recorder"

Recording performance [edit]

During the times of CD writer drives, they are oft marked with three dissimilar speed ratings. In these cases, the first speed is for write-once (R) operations, the 2d speed for re-write (RW) operations, and the last speed for read-only (ROM) operations. For example, a 40×/16×/48× CD writer drive is capable of writing to CD-R media at speed of forty× (6,000 kbit/s), writing to CD-RW media at speed of 16× (two,400 kbit/s), and reading from a CD-ROM media at speed of 48× (seven,200 kbit/southward).

During the times of combo (CD-RW/DVD-ROM) drives, an boosted speed rating (e.g. the 16× in 52×/32×/52×/xvi×) is designated for DVD-ROM media reading operations.

For DVD writer drives, Blu-ray Disc combo drives, and Blu-ray Disc author drives, the writing and reading speed of their respective optical media are specified in its retail box, user's manual, or bundled brochures or pamphlets.

In the late 1990s, buffer underruns became a very mutual problem as high-speed CD recorders began to appear in dwelling and function computers, which—for a multifariousness of reasons—often could not muster the I/O performance to go along the information stream to the recorder steadily fed. The recorder, should information technology run brusque, would exist forced to halt the recording process, leaving a truncated track that usually renders the disc useless.

In response, manufacturers of CD recorders began aircraft drives with "buffer underrun protection" (nether diverse trade names, such as Sanyo's "BURN-Proof", Ricoh's "JustLink" and Yamaha'southward "Lossless Link"). These can suspend and resume the recording procedure in such a mode that the gap the stoppage produces can exist dealt with by the fault-correcting logic built into CD players and CD-ROM drives. The first of these drives^{[ which? ]} were rated at 12× and 16×.

The first optical drive to back up recording DVDs at 16× speed was the Pioneer DVR-108, released in the 2d half of 2004. At that time however, no recordable DVD media supported that high recording speed all the same.^{[71] [72] [73]}

While drives are called-for DVD+R, DVD+RW and all Blu-ray formats, they practise not require any such error correcting recovery equally the recorder is able to place the new data exactly on the stop of the suspended write finer producing a continuous track (this is what the DVD+ technology achieved). Although later interfaces were able to stream data at the required speed, many drives now write in a 'zoned abiding linear velocity' ("Z-CLV"). This means that the drive has to temporarily suspend the write operation while information technology changes speed and then recommence it once the new speed is attained. This is handled in the same way every bit a buffer underrun.

The internal buffer of optical disc author drives is: viii MiB or 4 MiB when recording BD-R, BD-R DL, BD-RE, or BD-RE DL media; 2 MiB when recording DVD-R, DVD-RW, DVD-R DL, DVD+R, DVD+RW, DVD+RW DL, DVD-RAM, CD-R, or CD-RW media.

Recording schemes [edit]

CD recording on personal computers was originally a batch-oriented chore in that it required specialised authoring software to create an "paradigm" of the data to record and to record information technology to disc in the 1 session. This was acceptable for archival purposes, but express the full general convenience of CD-R and CD-RW discs as a removable storage medium.

Packet writing is a scheme in which the recorder writes incrementally to disc in brusk bursts, or packets. Sequential parcel writing fills the disc with packets from bottom upwardly. To brand it readable in CD-ROM and DVD-ROM drives, the disc can be closed at any time by writing a final table-of-contents to the commencement of the disc; thereafter, the disc cannot be packet-written whatever further. Packet writing, together with back up from the operating system and a file system like UDF, tin exist used to mimic random write-access equally in media like flash retentivity and magnetic disks.

Fixed-length packet writing (on CD-RW and DVD-RW media) divides upward the disc into padded, fixed-size packets. The padding reduces the chapters of the disc, but allows the recorder to start and finish recording on an individual packet without affecting its neighbours. These resemble the cake-writable access offered by magnetic media closely enough that many conventional file systems will work as-is. Such discs, however, are non readable in most CD-ROM and DVD-ROM drives or on most operating systems without additional third-party drivers. The segmentation into packets is non as reliable as it may seem as CD-R(W) and DVD-R(Due west) drives can only locate data to inside a information cake. Although generous gaps (the padding referred to above) are left between blocks, the drive even so can occasionally miss and either destroy some existing data or fifty-fifty return the disc unreadable.

The DVD+RW disc format eliminates this unreliability past embedding more accurate timing hints in the data groove of the disc and allowing private data blocks (or even bytes) to be replaced without affecting backward compatibility (a feature dubbed "lossless linking"). The format itself was designed to deal with discontinuous recording because information technology was expected to exist widely used in digital video recorders. Many such DVRs use variable-rate video compression schemes which require them to record in short bursts; some allow simultaneous playback and recording past alternating quickly betwixt recording to the tail of the disc whilst reading from elsewhere. The Blu-ray Disc arrangement besides encompasses this technology.

Mount Rainier aims to make packet-written CD-RW and DVD+RW discs every bit convenient to utilize equally that of removable magnetic media past having the firmware format new discs in the background and manage media defects (by automatically mapping parts of the disc which have been worn out past erase cycles to reserve space elsewhere on the disc). As of Feb 2007, back up for Mount Rainier is natively supported in Windows Vista. All previous versions of Windows crave a third-political party solution, equally does Mac OS X.

Recorder Unique Identifier [edit]

Owing to force per unit area from the music manufacture, as represented by the IFPI and RIAA, Philips developed the Recorder Identification Code (RID) to allow media to be uniquely associated with the recorder that has written it. This standard is independent in the Rainbow Books. The RID-Code consists of a supplier code (e.k. "PHI" for Philips), a model number and the unique ID of the recorder. Quoting Philips, the RID "enables a trace for each disc back to the exact machine on which it was made using coded data in the recording itself. The use of the RID code is mandatory."^[74]

Although the RID was introduced for music and video industry purposes, the RID is included on every disc written by every drive, including data and backup discs. The value of the RID is questionable as information technology is (currently) impossible to locate whatever individual recorder due to there beingness no database.

Source Identification Lawmaking [edit]

The Source Identification Lawmaking (SID) is an eight character supplier code that is placed on optical discs by the manufacturer. The SID identifies non simply manufacturer, but also the individual factory and auto that produced the disc.

According to Phillips, the administrator of the SID codes, the SID code provides an optical disc production facility with the means to place all discs mastered or replicated in its plant, including the specific Laser Beam Recorder (LBR) point processor or mould that produced a particular stamper or disc.^[74]

Use of RID and SID together in forensics [edit]

The standard use of RID and SID hateful that each disc written contains a record of the machine that produced a disc (the SID), and which drive wrote it (the RID). This combined noesis may be very useful to police force enforcement, to investigative agencies, and to individual or corporate investigators.^[75]

See too [edit]

• Computer hardware
• Cue sheet (music software)
• Floptical
• ISO image
• List of optical disc authoring software
• MultiLevel Recording
• Optical disc authoring
• Optical disc recording technologies
• Optical jukebox
• Phase-modify Dual
• Receiver (radio)
• Ripping

Notes [edit]

1. ^ The angular disc speeds of ×48 on CDs, ×16 on DVDs and ×12 on Blu-ray Discs refer to that equivalent linear velocity required for this multiple of the respective original speeds, if accessed at the outermost disc border, and amounts to similar physical rotation speeds.

References [edit]

1. ^ "QPxTool - bank check the quality". qpxtool.sourceforge.io.
2. ^ QPxTool - check the quality Listing of supported devices by dosc quality scanning software QPxTool']
3. ^ "Überbrennen von CD-Rs: Informationen". www.kautz-lucas.de (in German). Retrieved 13 August 2020.
4. ^ Video: "SAMSUNG ODD SE-S084D AV Connectivity" (published on September 14th 2010)
5. ^ TSSTcorp SE-208AB portable external DVD drive — User manual: Using "AV" mode (FAT32 file system simulation) (2011)
6. ^ "BluRay — Recording and reading speed". www.hughsnews.ca . Retrieved xi August 2020. At this early phase anticipating annihilation is merely speculation just it's possible to make some informed predictions. From a practical perspective, spinning an optical disc at 10,000 RPM has long proven the realistic limit for half-height drives and 5,000 RPM for slim-types.
7. ^ ^{a b c} Pioneer computer bulldoze archive
8. ^ Taylor, Jim H.; Johnson, Mark R.; Crawford, Charles K. (2006). DVD Demystified. McGraw-Loma Professional. pp. 7–8. ISBN0-07-142396-6.
9. ^ Stan, Sorin K. (1998). The CD-ROM Drive: A Cursory System Description. Springer. p. 13. ISBN0-7923-8167-X.
10. ^ "Violent Down A PS3 Blu Ray Bulldoze". Hackaday. 12 November 2019. Retrieved 31 July 2020.
11. ^ Thomann, Ralph (2005). "repair cd-thespian repairing cd-player cd-actor assist arrange cd-player repairing manual". www.ralph-toman.de . Retrieved 2020-07-31 .
12. ^ "Optical Scale: DVD Player Repair – Hungry Hacker". 2005-10-09. Retrieved 31 July 2020.
13. ^ Video: PS2 Potentiometer Adjustment - Disk Read Error Fix - YouTube (2015-06-06)
14. ^ Montesdeoca, Erik. "Repair Whatever CD,DVD, & BLURAY Player". www.instructables.com . Retrieved 31 July 2020.
15. ^ "How to Set DVD Writer Not Identifying the CD/DVD Media". TrishTech.com. 2 February 2016. Retrieved 31 July 2020.
16. ^ "Disc Read problems? How to POT Tweak Xbox 360 DVD Laser". Team-Xecuter Customs. 22 Feb 2011. Retrieved 31 July 2020.
17. ^ "100mW-Laserdioden aus 16x-DVD-Brennern" (PDF). mikrocontroller.net (in German language). Retrieved 11 August 2020.
18. ^ ^{a b c} "CD-Recordable FAQ - section 5". cdrfaq.org.
19. ^ "Compatibility of DVD".
20. ^ "5. Weather That Impact CDs and DVDs • CLIR". CLIR.
21. ^ "Light amplification by stimulated emission of radiation diodes from CD-RW drives can cut and burn!". danyk.cz . Retrieved 11 August 2020.
22. ^ "Powerful laser diodes from DVD-RW bulldoze". danyk.cz.
23. ^ "Cross Section of DVD+R DL Optical Media".
24. ^ "Cross Section of DVD+R DL Optical Media".
25. ^ http://www.blu-raydisc.com/Avails/Downloadablefile/White_Paper_General_5th_20180216.pdf
26. ^ "Life in the fast lane tin exist a disc-shattering experience". The Sydney Morning Herald. Dec 9, 2002.
27. ^ ^{a b} Andrawes, Mike. "Kenwood 52X TrueX EIDE CD-ROM". www.anandtech.com.
28. ^ Editor, H. H. (December 15, 2001). "Kenwood'southward 72X True X CDROM Drive". HotHardware.
29. ^ ^{a b} "KenWood 72x TrueX CD-ROM | CdrInfo.com". world wide web.cdrinfo.com.
30. ^ Aug 07, 2000. "Kenwood's 72X CD tin can't keep pace with 24X CD-RW -". GCN. {{cite spider web}}: CS1 maint: numeric names: authors list (link)
31. ^ "Target PC :: Kenwood 72X IDE CD-ROM". www.targetpc.com.
32. ^ "Kenwood launches 72x CD unit of measurement". www.theregister.com.
33. ^ https://pro.sony/s3/cms-static-content/file/49/1237494482649.pdf
34. ^ Page, M. Kenwood 72× CD-ROM Review. p. two. Archived from the original on 2012-03-01. Retrieved 2007-10-08 .
35. ^ Spurgeon, Brad (Dec 11, 2004). "Spinning out of control: Take a chance of CD explosion". The New York Times. Archived from the original on March 25, 2014.
36. ^ ^{a b} "View All Discontinued LG Burners & Drives". LG USA. Archived from the original on 2020-07-11. Retrieved 2020-07-11 .
37. ^ ^{a b} "Transmission".
38. ^ "DVR-107D, DVR-107BK General Specifications" (PDF). Pioneer Electronics USA. 2004. Retrieved 31 July 2020.
39. ^ Pioneer DVR-A06 brochure (2003)
40. ^ "Guide For Different Types Of Optical Drives". Tenpire. Retrieved 2019-06-12 .
41. ^ "| Wii - General Data: Organization & Accessories". Nintendo. Retrieved 2013-01-07 .
42. ^ "Video: "What Happens When you lot put a GameCube disc into a Nintendo Wii"". YouTube. Archived from the original on 2021-12-12.
43. ^ PlayStation 3 Instruction Manual (PDF). p. 50. Retrieved 2012-xi-12 .
44. ^ "Nintendo Back up: What Discs Are Uniform with the Wii U?". en-americas-support.nintendo.com.
45. ^ CD-210PU USB interface portable CD-ROM bulldoze. TEAC. Retrieved 2007-10-08 .
46. ^ LiteOn eTAU108 - DVD±RW (±R DL) / DVD-RAM drive - Hullo-Speed USB Serial Specification sheet and picture - CNet.com, 2009; accessed July 11th 2020.
47. ^ "cdvdcontrol • man page". helpmanual.io. 2014-02-26.
48. ^ Maximum PC – Conduct Year. December 2002. p. 30,80.
49. ^ Manpage for cdrecord.1
50. ^ "Calorie-free-On iHAS324 - Printer Friendly version". CDR info. 2009-07-14. Retrieved 14 August 2021. SmartWrite can overspeed certain 16X DVD±R media to a maximum of 24X
51. ^ ^{a b} "Picture of the front panel of a NEC CDR-502 with standalone CD playback control buttons".
52. ^ "Photograph of early CD-ROM drives with Audio CD control buttons and 3.5mm headphone plug".
53. ^ "cdtool". hinterhof.net. 2006-08-09. Retrieved 25 July 2020.
54. ^ "cdtool(one) [debian man page]". www.unix.com. 2004-07-29.
55. ^ ^{a b} "Computer Peripherals - Chapter 12. Optical Disks" (PDF). Nanyang Technological Academy, Singapore. October 16, 2001. Retrieved 2011-07-16 .
56. ^ ^{a b} Lasers & Optronics, Book 6, folio 77
57. ^ Enterprise, I. D. K. (September 19, 1983). "Computerworld". IDG Enterprise – via Google Books.
58. ^ Japanese PCs (1984) (xiv:24), Computer Chronicles
59. ^ Faulkner, Joey (September 24, 2012). "MiniDisc, the forgotten format". The Guardian . Retrieved May 30, 2019.
60. ^ Taylor, Jim (March 21, 1997). "DVD Frequently Asked Questions (with answers!)". Video Discovery. Archived from the original on March 29, 1997. Retrieved August 20, 2019.
61. ^ Staff (March 24, 1997). "Creative Does DVD". PC Gamer. Archived from the original on February 18, 1998. Retrieved December v, 2019.
62. ^ "Press Release". www.kenwood.com.
63. ^ "Sony Shows 'DVR-Bluish' Prototype". CD R Info. October xi, 2000. Retrieved October 17, 2007.
64. ^ Liadov, Maxim. "Sony BDZ-S77 Recorder Review". Digit-Life . Retrieved October nineteen, 2007.
65. ^ "Exclusive TDK Durabis Coating Technology Makes Cartridge-Free, Ultra-Durable Blu-ray Discs a Reality". Phys.Org. January nine, 2005. Retrieved October xviii, 2007.
66. ^ Costa, Dan (June 15, 2006). "Samsung Ships the First Blu-ray Histrion". PCMag.com . Retrieved October 17, 2007.
67. ^ Sony Rearranges Blu-ray Release Schedule. High-Def Assimilate, June 15, 2006.
68. ^ "Sony Unveils First Blu-Ray Disc Drive Burner". Sony. July eighteen, 2006. Retrieved Jan 22, 2010.
69. ^ Hollister, Sean. "Ever own a computer with a DVD drive? You may exist owed $10". CNET.
70. ^ "CD-R/DVD ROM Compatibility Study - Introduction". 2002-02-03. Archived from the original on 2002-02-03. Retrieved 2020-07-xx .
71. ^ "Pioneer DVR-108: 16x-DVD-Brenner im PC-WELT-Exam" (PCwelt.de, 2004-08-12) (German language)]
72. ^ "16fach-DVD-Brenner Pioneer DVR-108 Der schnellste DVD-Brenner" − CHIP.DE (2004-10-16) (German language)
73. ^ Pioneer DVR-108 – Product information and specifications
74. ^ ^{a b} "Intellectual Property & Standards/Licensing Programs". Philips. Retrieved 2010-07-27 .
75. ^ "Pocket guide to recognising pirate music products" (PDF). International Federation of the Phonographic Industry. Retrieved 2010-07-27 .

External links [edit]

• How CDs Work at HowStuffWorks
• How CD Burners Work at HowStuffWorks
• Understanding CD-R & CD-RW

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Source: https://en.wikipedia.org/wiki/Optical_disc_drive#:~:text=In%20computing%2C%20an%20optical%20disc,to%20or%20from%20optical%20discs.

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