What is a DVD?
A DVD (digital versatile disc) basically plays movies.
DVD stands (originally) for Digital Video Disc, or officially, Digital Versatile Disc. It was created as a high-density data medium for movie storage and playback within the home. The specifications for the format are released and maintained by the DVD Forum, which is a cartel of hardware manufacturers and other corporations with an interest in the digital entertainment content industry. A DVD is a 120mm optical disk, very similar in appearance to the earlier Compact Disc format. They key differences between DVD and CD are a much higher data density, and the ability to record up to two data layers per side of the disk.
DVD comes in a number of physical formats and sizes used for a variety of different purposes. The format usually used for movie releases is known as a DVD-ROM (Read Only Memory) indicating that data can only be read from the disk, not written to it. A number of slightly different technologies make recordable DVDs available. These include:
- DVD-ROM Read Only Memory, which is typically stamped in
a DVD press, not burnt, and can only be read from.
Any mass-produced DVD title is on a DVD-ROM disk;
- DVD±R Recordable, which can usually be written to once in a long, continuous write in a DVD burner;
- DVD±RW Re-Writable, which are disks that are rated to be burned up to 100 times;
- DVD-RAM Random Access Memory, which can be used almost like a portable hard disk, with any one spot on the disk surface rated to be written to up to 100,000 times.