What Does Digital Versatile Disk Rewritable Mean?
Digital versatile disk rewritable (DVD-R) is a write-once (read only) digital versatile disc used to permanently store data files. It is an optical disc that generally has a storage capacity of 4.71 gigabytes (GB/s), seven times larger than a compact disc rewritable (CD-R) that holds around 700 megabytes (MB/s). When both sides of a DVD-R are writable, it can store up to 17 GB/s of data.
The DVD-R is one of the three industry standards for DVD recordable formats; the other two are DVD–Random Access Memory (DVD-RAM) and DVD+Recordable (DVD+R). DVD-RAM can be continuously erased and recorded. It is only compatible with devices that support the DVD-RAM format. A DVD+R can record data once; the data on the disc is permanent. The DVD-R is similar to the DVD+R but has two additional standards. The general DVD-R(g) uses 635 nanometer (nm) recording wavelength; the DVD-R(a) for authoring has 650 nm recording wavelength for copy protection. Generally the DVD-R(a) for authoring is not available to the public. Both standards can read each other’s format but cannot write each other’s format.
This term is also known as DVD-rewritable.
Techopedia Explains Digital Versatile Disk Rewritable
The dash, or “-R,” is in reference to the Pioneer Corporation standard format created in 1997. In 2002 the DVD+RW Alliance generated the “+R” recordable format which offered improved recording reliability. The “+R” also has less errors when recording in multi-sessions and when playing back at higher speeds.
The DVD-R was first manufactured in 1997 by the Pioneer Corporation. It could store approximately 3.95 GB/s of data. The DVD-R supports the majority of DVD players and is accepted by the DVD Forum, an international organization that uses and develops DVD as well as HD DVD formats for hardware, software and media. By 2000, the DVD-R had an industry standard of 4.7 GB/s.
The data on a DVD-R can be "written to" only once and cannot be changed. However, if the total amount of data written is not more than the disc capacity, then additional data can be added in what is known as multi-session – a recordable format allowing recording in sessions if there is free space left on the disc.
Although it is the same size (five inches in diameter and 1.2 mm thick) as a CD-R, the DVD-R has far greater storage capacity due to the smaller track pitch and reduced pitch size. The track pitch that guides the laser beam on the grove spiral is a lot smaller but can hold more data, referred to as pits. The pits are constructed by a red laser beam that has a wavelength of 640 nanometers (nm/s); a CD-R uses a wavelength of 780 nm.