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Optical disc authoring Optical disc authoring, including CD, DVD, and Blu-ray Disc authoring, is the process of assembling source material—video, audio or other data—into the proper logical volume format to then be recorded ("burned") onto an optical di ...
requires a number of different optical disc recorder technologies working in tandem, from the
optical disc An optical disc is a flat, usuallyNon-circular optical discs exist for fashion purposes; see shaped compact disc. disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid o ...
media to the
firmware In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, h ...
to the control electronics of the
optical disc drive 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. Some drives can on ...
.


Types of recordable optical disc

There are numerous formats of recordable optical direct to disk on the market, all of which are based on using a
laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radi ...
to change the
reflectivity The reflectance of the surface of a material is its effectiveness in Reflection (physics), reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the respon ...
of the
digital recording In digital recording, an audio signal, audio or video signal is converted into a stream of discrete numbers representing the changes over time in air pressure for audio, or Color, chroma and luminance values for video. This number stream is s ...
medium in order to duplicate the effects of the pits and lands created when a commercial optical disc is pressed. Emerging technologies such as holographic data storage and 3D optical data storage aim to use entirely different data storage methods, but these products are in development and are not yet widely available. The earliest form is
magneto-optical A magneto-optical drive is a kind of optical disc drive capable of writing and rewriting data upon a magneto-optical disc. 130 mm (5.25 in) and 90 mm (3.5 in) discs are the most common sizes. In 1983, just a year after t ...
, which uses a magnetic field in combination with a laser to write to the medium. Though not widely used in consumer equipment, the original
NeXT NeXT, Inc. (later NeXT Computer, Inc. and NeXT Software, Inc.) was an American technology company headquartered in Redwood City, California that specialized in computer workstations for higher education and business markets, and later develope ...
cube used MO media as its standard storage device, and consumer MO technology is available in the form of
Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...
's
MiniDisc MiniDisc (MD) is an erasable magneto-optical disc-based data storage format offering a capacity of 60, 74, or 80 minutes of digitized audio. Sony announced the MiniDisc in September 1992 and released it in November of that year for sale i ...
. This form of medium is rewriteable. The most common form of recordable optical media is write-once organic dye technology, popularized in the form of the
CD-R CD-R (Compact disc-recordable) is a digital media, digital optical disc data storage device, storage format. A CD-R disc is a compact disc that can only be Write once read many, written once and read arbitrarily many times. CD-R discs (CD-Rs) ...
and still used for higher-capacity media such as
DVD-R DVD recordable and DVD rewritable are a collection of optical disc formats that can be written to by a DVD recorder and by computers using a DVD writer. The "recordable" discs are write-once read-many (WORM) media, where as "rewritable" discs a ...
. This uses the laser alone to scorch a transparent organic dye (usually
cyanine Cyanines, also referred to as tetramethylindo(di)-carbocyanines are a synthetic dye family belonging to the polymethine group. Although the name derives etymologically from terms for shades of blue, the cyanine family covers the electromagnetic s ...
,
phthalocyanine Phthalocyanine () is a large, aromatic, macrocyclic, organic compound with the formula and is of theoretical or specialized interest in chemical dyes and photoelectricity. It is composed of four isoindole units linked by a ring of nitrogen ato ...
, or
azo compound Azo compounds are organic compounds bearing the functional group diazenyl (, in which R and R′ can be either aryl or alkyl groups). IUPAC defines azo compounds as: "Derivatives of diazene (diimide), , wherein both hydrogens are substituted ...
-based) to create "pits" (i.e. dark spots) over a reflective spiral groove. Most such media are designated with an R (recordable) suffix. Such discs are often quite colorful, generally coming in shades of blue or pale yellow or green. Rewritable, non-magnetic optical media are possible using phase change alloys, which are converted between crystalline and amorphous states (with different reflectivity) using the heat from the drive
laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radi ...
. Such media must be played in specially tuned drives, since the phase-change material has less of a contrast in reflectivity than dye-based media; while most modern drives support such media, many older CD drives cannot recognize the narrower threshold and cannot read such discs. Phase-change discs are designated with RW (ReWriteable) or RE (Recordable-Erasable). Phase-change discs often appear dark grey. Another technology creates pits in an inorganic carbon layer, a "write-once" option. Created by Millenniata,
M-DISC M-DISC (Millennial Disc) is a Write once read many, write-once Optical disc recording technologies, optical disc technology introduced in 2009 by Millenniata, Inc. and available as DVD and Blu-ray discs. Overview M-DISC's design is intended t ...
, records data on special M-DISC with a data life-time of several hundred years.M-Disc
millenniata.com. 2010-11-24. Retrieved 20-10-08


Optimum Power Calibration

Optimum Power Calibration (OPC) is a function that checks the proper laser power for writing a particular session in the media in use. More sophisticated is ''Active OPC'', which calculates the optimum laser power and adjusts it in real-time.


Recording modes

Optical discs can be recorded in Disc At Once, Track At Once, Session at Once (i.e. multiple burning sessions for one disc), or
packet writing Packet writing (or incremental packet writing, IPW) is an optical disc recording technology used to allow write-once and rewritable CD and DVD media to be used in a similar manner to a floppy disk from within the operating system. Details Pa ...
modes. Each mode serves different purposes: *Disc At Once: writes the entire disc in one pass; preferred for duplication masters *Track At Once: writes individual tracks with a gap between tracks; used for audio CDs *Session At Once: writes and finalizes multiple sessions on one CD; usually not supported for CD Audio, and not universally supported by authoring software *Packet writing: writes data to the medium on demand (see below)


Connection technologies

Unlike early
CD-ROM A CD-ROM (, compact disc read-only memory) is a type of read-only memory consisting of a pre-pressed optical compact disc that contains computer data storage, data computers can read, but not write or erase. Some CDs, called enhanced CDs, hold b ...
drives, optical disc recorder drives have generally used industry standard connection protocols. Early computer-based CD recorders were generally connected by way of
SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices, best known for its use with storage devices such as hard disk drives. SCSI was introduced ...
; however, as SCSI was abandoned by its most significant users (particularly
Apple Computer Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Computer Co ...
), it became an expensive option for most computer users. As a result, the market switched over to
Parallel ATA Parallel ATA (PATA), originally , also known as Integrated Drive Electronics (IDE), is a standard interface designed for IBM PC-compatible computers. It was first developed by Western Digital and Compaq in 1986 for compatible hard drives and C ...
connections for most internal drives; external drives generally use PATA drive mechanisms connected to a bridge inside the case that connects to a high-speed serial bus such as
FireWire IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony a ...
or Hi-Speed USB 2.0. Nearly all modern drives, particularly
Blu-ray Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-defin ...
drives use
Serial ATA SATA (Serial AT Attachment) is a computer bus interface that connects host adapter, host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PAT ...
. Standalone recorders use standard A/V connections, including
RCA connector The RCA connector is a type of electrical connector commonly used to carry analog audio and video signals. The name refers to the popular name of Radio Corporation of America, which introduced the design in the 1930s. Typically, the output i ...
s, TOSlink, and
S/PDIF S/PDIF (Sony/Philips Digital Interface) is a type of digital audio interface used in consumer audio equipment to output audio over relatively short distances. The signal is transmitted over either a coaxial cable using RCA connector, RCA or BN ...
for audio and RF,
composite video Composite video, also known as CVBS (composite video baseband signal or color, video, blanking and sync), is an analog video format that combines image information—such as brightness (luminance), color (chrominance), and synchronization, int ...
,
component video Component video is an analog video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video (CAV) information that is transmitted or stored as three separate signals. Compo ...
,
S-Video S-Video (also known as separate video, Y/C, and erroneously Super-Video) is an analog video signal format that carries standard-definition video, typically at 525 lines or 625 lines. It encodes video luma and chrominance on two separate chann ...
,
SCART SCART (also known as or , especially in France, 21-pin EuroSCART in marketing by Sharp Corporation, Sharp in Asia, Euroconector in Spain, EuroAV or EXT, or EIA Multiport in the United States, as an EIA interface) is a French-originated standard ...
, and
FireWire IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony a ...
for video. High-bandwidth digital connections such as
HDMI High-Definition Multimedia Interface (HDMI) is a proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gam ...
are unlikely to feature as recorder devices are not permitted to decrypt the
encrypted In cryptography, encryption (more specifically, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plain ...
video content.


Overburning

Overburning is the process of recording data past the normal, vendor-specified size limit of the recordable media. Structures in the ATIP do not allow such sizes to be specified. Overburning may be used to determine the actual capacity limit of a recordable disc, since the capacity rated by recordable disc vendors merely is the ''guaranteed'' capacity, beyond which the actual capacity is indefinite. Data located beyond the specified capacity is not guaranteed to be readable.''"Overburning: 100 Minutes On An Audio CD"''
– by Frank Völkel of TomsHardware – April 11, 2002


Buffer underrun protection

Usually, the recorder must perform a complete write without pauses. Once the laser is on, stopping and restarting the recording process may introduce flaws. A
buffer underrun In computing, buffer underrun or buffer underflow is a state occurring when a buffer used for communicating between two devices or processes is fed with data at a lower speed than the data is being read from it. This requires the program read ...
occurs during recording if the supply of data to the recorder is interrupted before the write is complete. Software typically moves the data to be recorded into a
buffer Buffer may refer to: Science * Buffer gas, an inert or nonflammable gas * Buffer solution, a solution used to prevent changes in pH * Lysis buffer, in cell biology * Metal ion buffer * Mineral redox buffer, in geology Technology and engineeri ...
; underrun occurs if the recorder processes data in the buffer faster than the software reloads it. Historically, buffer underrun was often caused by writing data obtained from a slow device, or by slowness of the recording software, from a slow processor or a processor executing other tasks concurrently. Various recorders minimize or cope with buffer underrun in the following ways: *Nearly all burners can slow the rotation of the disc and record at a slower rate. A burner may do so on sensing that it is drawing down the data in the buffer faster than software is reloading it. *Recording software maintains larger buffers than when CD recorders were first introduced. Some recorders maintain their own buffer memory independently of the computer. This additional buffering ensures that momentary pauses in the supply of data do not cause buffer underrun. *Some recorders are, in fact, able to stop writing in the middle of a session, and resume writing whenever the buffer is refilled. Recorders with such buffer underrun protection handle the interruption with an extremely small gap in the recorded track on the disc. Since the techniques for protecting against buffer underrun are proprietary and vendor-specific, technical details vary. *DVD+R, DVD+RW and the recordable
Blu-ray Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-defin ...
formats are immune from buffer underrun as these discs contain technology that allows the recorder's write mechanism to precisely locate the end of the recorded track and to seamlessly carry on from where it left off. Many disc authoring utilities disable the buffer underrun protection option when these discs are being written. Buffer underrun is minimized by a strategy in which the recorder burns a packet rather than an entire session or an entire disc. When using
rewritable media Computer data storage or digital data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers. The central processin ...
(
CD-RW RW (Compact Disc-Rewritable) is a digital media, digital optical disc data storage device, storage format introduced by Ricoh in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written. CD-RWs, as opposed to CDs, r ...
,
DVD-RW DVD recordable and DVD rewritable are a collection of optical disc formats that can be written to by a DVD recorder and by computers using a DVD writer. The "recordable" discs are write-once read-many (WORM) media, where as "rewritable" discs a ...
,
DVD-RAM DVD-RAM (DVD Random Access Memory) is a DVD-based disc specification presented in 1996 by the DVD Forum, which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media have been used in computers as well as camcorde ...
), the UDF file system organizes the disc into packets that are written individually. The packets are referenced by a single, updated address table.


Specific proprietary technologies


''Sanyo'' BURN-Proof

BURN-Proof (Buffer Underrun-Proof) is a proprietary technology for buffer underrun protection developed by
Sanyo is a former Japanese electronics manufacturer founded in 1947 by Toshio Iue, the brother-in-law of Kōnosuke Matsushita, the founder of Matsushita Electric Industrial, now known as Panasonic. Iue left Matsushita Electric to start his own bu ...
.


''Asus'' FlextraLink

FlextraLink is a proprietary technology for buffer underrun protection developed by
Asus ASUSTeK Computer Inc. (, , , ; stylized as ASUSTeK or ASUS) is a Taiwanese Multinational corporation, multinational computer, phone hardware and electronics manufacturer headquartered in Beitou District, Taipei, Taiwan. Its products include deskto ...
. FlextraSpeed continuously monitors the recording media and sets the optimal writing speeds to ensure best recording quality, for discs that can’t withstand high-speed burning.


''Sony'' Power Burn

Power Burn is a proprietary technology for buffer underrun protection, developed by
Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...
. Features: * Buffer underrun protection: When a
buffer underrun In computing, buffer underrun or buffer underflow is a state occurring when a buffer used for communicating between two devices or processes is fed with data at a lower speed than the data is being read from it. This requires the program read ...
occurs, the drive suspends writing. The drive memorizes the end writing point and timing, and immediately resumes writing from that exact point when sufficient data is filled in the buffer memory. * Protection from write errors caused by shock and vibration: PowerBurn's Shock Proof technology pauses writing when the device is moved, and resumes after the drive becomes stable. This allows it to work in a mobile environment. * Optimization of write conditions: The drive detects characteristics of each individual medium and optimizes all key writing conditions such as writing speed, laser power and write strategy.


''Yamaha'' SafeBurn

SafeBurn is a proprietary technology for buffer underrun protection developed by
Yamaha Corporation is a Japanese multinational musical instrument and audio equipment manufacturer. It is one of the constituents of Nikkei 225 and is the world's largest musical instrument manufacturing company. The former motorcycle division was establishe ...
.


Packet writing

Packet writing is a technology that allows optical discs to be used in a similar manner to a
floppy disk A floppy disk or floppy diskette (casually referred to as a floppy, a diskette, or a disk) is a type of disk storage composed of a thin and flexible disk of a magnetic storage medium in a square or nearly square plastic enclosure lined with a ...
. Packet writing can be used both with once-writeable media and rewriteable media. Several competing and incompatible packet writing disk formats have been developed, including DirectCD and InCD. The standardized formats for packet writing are the
Universal Disk Format Universal Disk Format (UDF) is an open, vendor-neutral file system for computer data storage for a broad range of media. In practice, it has been most widely used for DVDs and newer optical disc formats, supplanting ISO 9660. Due to its desig ...
in the plain, VAT, and spared builds.


Simulated writing

Using the ''simulated writing'' or ''simulated burning'' feature of
optical disc authoring Optical disc authoring, including CD, DVD, and Blu-ray Disc authoring, is the process of assembling source material—video, audio or other data—into the proper logical volume format to then be recorded ("burned") onto an optical di ...
software, the writing process will be simulated, which means that the disc spins and the laser moves as if on an actual writing process, but without any data being recorded to the disc. This feature allows for observing the writing speeds and patterns (e.g. constant angular velocity, constant linear velocity and P-CAV and Z-CLV variants) with different writing speed settings and testing the highest capacity of an individual disc that would be achievable using overburning. This feature is standardized on
CD-R CD-R (Compact disc-recordable) is a digital media, digital optical disc data storage device, storage format. A CD-R disc is a compact disc that can only be Write once read many, written once and read arbitrarily many times. CD-R discs (CD-Rs) ...
,
CD-RW RW (Compact Disc-Rewritable) is a digital media, digital optical disc data storage device, storage format introduced by Ricoh in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written. CD-RWs, as opposed to CDs, r ...
,
DVD-R DVD recordable and DVD rewritable are a collection of optical disc formats that can be written to by a DVD recorder and by computers using a DVD writer. The "recordable" discs are write-once read-many (WORM) media, where as "rewritable" discs a ...
and
DVD-RW DVD recordable and DVD rewritable are a collection of optical disc formats that can be written to by a DVD recorder and by computers using a DVD writer. The "recordable" discs are write-once read-many (WORM) media, where as "rewritable" discs a ...
, but not on DVD+R and
DVD+RW DVD recordable and DVD rewritable are a collection of optical disc formats that can be written to by a DVD recorder and by computers using a DVD writer. The "recordable" discs are write-once read-many (WORM) media, where as "rewritable" discs a ...
, on which only
Plextor Plextor (styled PLEXTOR) ( zh, 浦科特; ) is a Taiwanese (formerly Japanese) consumer electronics brand, best known for solid-state drives and optical disc drives. Company The brand name Plextor was used for all products manufactured by the El ...
optical drives support simulated writing so far.


Longevity

Retail recordable/writable optical media contain dyes in/on the optical media to record data, whereas factory-manufactured optical media use physical "pits" created by plastic molds/casts. As a result, data storage on retail optical media does not have the life-span of factory-manufactured optical media. The problem is exacerbated because as the writing laser of the recorder is used, its power output drops with age - typically after just a few years. Consequently, a disc written with a laser that is nearing the end of its useful life may not have a readable life that is as long as if a new laser had been used. Dye based optical media should not be solely relied on to archive valuable data. MAM-A (
Mitsui is a Japanese corporate group and '' keiretsu'' that traces its roots to the ''zaibatsu'' groups that were dissolved after World War II. Unlike the ''zaibatsu'' of the pre-war period, there is no controlling company with regulatory power. Ins ...
) claims a life of 300 years on their archival gold CD-R and 100 years for gold DVDs. Good alternatives would be to additionally backup one's media using other media technologies and/or investing in
non-volatile memory Non-volatile memory (NVM) or non-volatile storage is a type of computer memory that can retain stored information even after power is removed. In contrast, volatile memory needs constant power in order to retain data. Non-volatile memory typ ...
technologies.Results of research by the U.S. Library of Congress on the reliability of backups on optimal media https://www.loc.gov/preserv/rt/projects/cd-r_dvd-r_rw_longevity.html A series of follow-up studies conducted by the Canadian Conservation Institute in 2019 revealed that ''CD-R'' with phthalocyanine-dye and a gold-metal layer had the greatest longevity at over 100 years when stored at ideal temperature and humidity-levels. The second longest was ''DVD-R (gold-metal layer)'' with an average longevity of 50-100 years under ideal conditions. ''CD-R'' with phthalocyanine and a silver-metal-alloy layer also scored an average longevity of 50-100 years, ''however'', the researchers noted that if the storage environment contains pollutants any CD-Rs that used a silver layer would likely degrade faster than discs with a gold layer. The researchers concluded the silver layer discs may not be a suitable solution for applications where longevity is important. Both CD-R and DVD-R outperformed all forms of
Blu-ray Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-defin ...
disc in regards to longevity: the best performing Blu-ray disc, the BD-RE (rewritable Blu-ray) has an average longevity of 20-50 years, while non-rewritable
BD-R Blu-ray Disc Recordable (BD-R) and Blu-ray Disc Recordable Erasable (BD-RE) refer to two direct-to-disk recording, direct to disc optical disc recording technologies that can be recorded on to a Blu-ray-based optical disc with an optical disc ...
discs have an average longevity of 10-20 years under ideal conditions.


See also

* CD and DVD writing speed * MODS Disc * Optical disc recording modes * Write strategy


References


External links


Understanding CD-R & CD-RW
by Hugh Bennett
Understanding Recordable & Rewritable DVD
by Hugh Bennett


CD and DVD Longevity: How Long Will They Last?

Blu Ray Technology
{{DEFAULTSORT:Optical Disc Recording Technologies Compact disc Optical computer storage media Computer storage technologies