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Information about Dvd Rw

Optical disc authoring
Optical media types
Standards
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A spindle with discs of the DVD+RW format
DVD+RW is the name of a standard for optical discs: one of several types of DVD, which hold up to about 4.7GB per disc (interpreted as approximately 4.7 × 109 bytes; actually 2295104 sectors of 2048 bytes each) and are used for storing films, music or other data.

DVD+RW supports random write access, which means that data can be added and removed without erasing the whole disc and starting over (up to about 1000 times). With suitable support from the operating system, DVD+RW media can thus be treated like a large floppy disk, in contrast to DVD-RW which must be erased before re-writing can take place.

DVD+RW was primarily developed for holding discrete data sets (which change with time) or as recyclable discs for backing up collections of files. However, they (and DVD-RW) are less popular for computer use than DVD-R or DVD+R discs, because they are not suitable for permanent backup files (because non-rewritable media is significantly cheaper). For similar reasons, rewritable discs are not as widely used for permanent storage of home DVD video recorders as DVD-R and DVD+R.

On the other hand, DVD+RW or DVD-RW make an inexpensive medium for multiple temporary recordings: they can be used for the daily discs of a backup cycle (which are overwritten after a number of days or weeks), and became very popular for their convenience and cheapness as a medium for time-shifting TV (recording programs for a single later viewing and erasing), DVD+RW discs are now playable in three quarters of today's DVD players, many of them Hybrid (DVD±RW) drives.

Computer operating system support

Writeable DVDs can be burnt on Unix-like operating systems such as Linux with the program growisofs. They can be mounted onto the file system like any other block device.

Windows XP can read DVDs and can burn recordable discs; but it cannot burn rewritable DVDs without add-on software. However, most new and upgraded PCs have a drive (and software) which can read and write all formats, except DVD-RAM, which fewer people use at the moment.

All rewritables (DVD+RW, DVD-RW, and DVD-RAM) can be burned natively from the Windows Vista and Mac OS X operating systems, and the GNOME and KDE desktop environments (the latter using K3b).

Technical details

The recording layer in DVD+RW and DVD-RW discs is a phase change metal alloy (often GeSbTe) whose crystalline phase and amorphous phase have different reflectivity. The states can be switched depending on the power of the writing laser, so data can be written, read, erased and re-written. DVD-R and DVD+R discs use an organic dye.

History of the DVD+RW standard

The rewritable DVD+RW standard was formalized earlier than the non-rewritable relation DVD+R (the opposite was true with the DVD- formats). Although credit for developing the standard is often attributed unilaterally to Philips, it was "finalized" in 1997 by a coalition of corporations known as the DVD+RW Alliance. It was then abandoned until 2001, when it was heavily revised (in particular, the capacity increased from 2.8 GB to 4.7GB) and commercial products started to arrive (initially, only cheaper and "no-name" recorders) even though the standard was not approved by the DVD Forum (which produced a competing standard, DVD-RW)

However, the "random" rewriting made the DVD+RW format popular. Originally, the branded manufacturers except Philips only made pure DVD-RW recorders and players, but they could not ignore consumer preferences indefinitely.

See also

External links

optical disc authoring, including DVD authoring, known often as burning, is the process of recording source material—video, audio or other data—onto an optical disc (compact disc or DVD).
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optical disc is a flat, circular, usually polycarbonate disc where data is stored in the form of pits (or bumps) within a flat surface, usually along a single spiral groove that covers the entire recorded surface of the disc.
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disk image is a computer file containing the complete contents and structure of a data storage medium or device, such as a Hard drive, CD or DVD. The term has been generalized to cover any such file, whether originated from an actual physical storage device or not.
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optical disk drive (ODD) is a disk drive that uses electromagnetic waves as part of the process of reading and writing data. It is a computer's peripheral device, that stores data on optical discs.
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Optical disc authoring software is computer software for authoring optical discs including CD-ROMs and DVDs. They are also known by synonyms such as CD burning application or DVD authoring software. Such software is required to use an optical disc recorder.
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Disc At Once, Track At Once, Session at Once (i.e. multiple burning sessions for one disc), or packet writing modes. Each mode serves different purposes:
  • Disc At Once: writes the entire disc in one pass; preferred for duplication masters

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Disc-At-Once, Track-At-Once, and Session-At-Once.

CD Disc-At-Once

Disc-At-Once or DAO for CD-R media is a mode that masters the disc contents in one pass, rather than a track at a time as in Track At Once.
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Packet writing is an optical disc recording technology used to allow writeable CD and DVD media to be used in a similar manner to a floppy disk. Packet writing allows the user to access the contents of a CD-R or CD-RW disc directly through a mounted filesystem (Unix, Linux, Mac OS
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Laserdisc

Laserdisc (left) compared to a DVD (right).
Media type: Optical disc
Encoding: Various
Developed by: MCA
Usage: Video storage

Optical disc authoring
  • Optical disc
  • Optical disc image
  • Recorder hardware
  • Authoring software

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Compact Disc

The closely spaced tracks on the readable surface of a Compact Disc cause light to diffract into a full visible colour spectrum
Media type: Optical disc
Encoding: Various
Capacity: Typically up to 700 MB
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CD-ROM (an abbreviation of "Compact Disc read-only media") is a Compact Disc that contains data accessible by a computer. While the Compact Disc format was originally designed for music storage and playback, the format was later adapted to hold any form of binary data.
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CD-R (Compact Disc-Recordable) is a variation of the Compact Disc invented by Philips and Sony. CD-R is a Write Once, Read Many optical medium (though the whole disk does not have to be entirely written in the same session) and retains a high level of
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Compact Disc ReWritable (CD-RW) is a rewritable optical disc format. Known as CD-Erasable (CD-E) during its development, CD-RW was introduced in 1997, and was preceded by the never officially released CD-MO in 1988.
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MiniDisc

The Sony MZ1 MiniDisc player, the first to hit the market in 1992.
Media type: Magneto-optical disc
Encoding: ATRAC, linear PCM (with Hi-MD)
Capacity: 80 min (standard MiniDisc), up to 45 hours of audio (1 GB capacity) (with Hi-MD)
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DVD

Media type: Optical disc
Capacity: 4.7 GB (single layer), 8.5 GB (dual layer)
Usage: Data storage, audio, video, games

Optical disc authoring
  • Optical disc
  • Optical disc image
  • Recorder hardware
  • Authoring software

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DVD-R is a DVD recordable format. A DVD-R has a larger storage capacity than its optical predecessor, the 700 MB CD-R, typically storing 4.71 GB (or 4.382 GiB), although the capacity of the original standard developed by Pioneer was 3.95 GB (3.68 GiB).
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DVD-D is a self-destructing disposable DVD format. Like the EZ-D, it is sold in a cardboard sleeve, and begins to destroy itself after several hours.

DVD-D now exists as one time play only for movies, limited time play for video games, and recordable DVD-D.
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DVD-R DL (DL stands for Dual Layer), also called DVD-R9, is a derivative of the DVD-R format standard. DVD-R DL discs employ two recordable dye layers, each capable of storing nearly the 4.7 GB (4.
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DVD+R is a once-writable optical disc with 4.7 GB (4.377 GiB) of storage capacity (more precisely, 2295104 sectors of 2048 bytes each). It has slightly less storage capacity than the DVD-R (4.382 GiB).
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DVD+R DL (DL stands for Dual Layer, commonly mistaken as Double Layer), also called DVD+R9, is a derivative of the DVD+R format created by the DVD+RW Alliance. Its use was first demonstrated in October 2003.
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DVD-RW disc ("DVD dash RW", sometimes nicknamed "DVD minus RW") is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB. The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum.
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DVD-RW DL is a rewritable optical disc standard with storage capacity of 8.5 GB. DVD-RW DL discs employ two rewritable dye layers. It's approved by DVD Forum as "DVD Specifications for Re-recordable Disc for Dual Layer (DVD-RW for DL) Physical Specifications, Version 2.0".
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DVD+RW DL is a rewritable optical disc with storage capacity of 8.5 GB. DVD+RW DL discs employ two rewritable dye layers.

In March 2006, the DVD+RW Alliance approved DVD+RW part 2: Dual Layer, volume 1; DVD+RW 8.5 Gbytes, Basic Format Specifications, version 1.
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DVD-RAM (DVD–Random Access Memory) is a 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 camcorders and personal video recorders since 1998.
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Blu-ray Disc

Media type: High-density optical disc
Encoding: MPEG-2, MPEG-4 AVC (H.264), and VC-1
Capacity: 25 GB (single layer), 50 GB (dual layer)
Read mechanism: 1x@36 Mbit/s & 2x@72 Mbit/s
Developed by: Blu-ray Disc Association
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Blu-ray Disc recordable refers to two optical disc formats that can be recorded with an optical disc recorder. BD-R discs can be written to once, whereas BD-RE can be erased and re-recorded multiple times.
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HD DVD

Media type: High-density optical disc
Encoding: VC-1, H.264, and MPEG-2
Capacity: 15 GB (single layer) 30 GB (dual layer)
Read mechanism: 1x@36 Mbit/s & 2x@72 Mbit/s
Developed by: DVD Forum
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HD DVD-R is the writable disc variant of HD DVD, and is available with a single-layer capacity of 15 GB or dual-layer capacity of 30 GB.[1] Currently, HD DVD-R has slower write speeds than the competing BD-R format (1–2x vs.
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This article contains information about a scheduled or expected .
It may contain preliminary information that does not reflect the final version of the product.

HD DVD-RAM
Media type: High-density optical disc
Capacity: 20 GB
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Ultra Density Optical (UDO) is an optical disc format designed for high-density storage of high-definition video and data.

Overview

An Ultra Density Optical disc or UDO is a 5.25" ISO cartridge optical disc which can store up to 60 GB of data.
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