DVD
DVD stands for Digital Versatile Disc. It was originally referred to as Digital Video Disc.
The purpose of developing DVDs was to create a medium which could hold significantly more data than a CD-ROM. You can store two layers of data on each side of a DVD. The first layer can hold 4.7 GB and the second layer 3.8 GB, which means that a single-sided DVD can store 8.5 GB of data. DVDs can only be read by DVD drives, which can also read CD-ROMs. Unfortunately many DVD drives are not able to read CD-Rs. Even fewer can read CD-RWs.
Currently the following types of DVD are available:
- DVD-Audio: A high capacity audio medium.
- DVD-R: DVD-Rs can store between 3.95, 4.7 and 9.4 GB of data. In order to store 9.4 GB, you must use the second side of the DVD-R which means that you have to turn it over.
- DVD-RAM: This is a rewritable medium which can store either 2.6 GB (one layer) or 5.2 GB (two layers) of data.
- DVD-ROM: This is the data medium.
- DVD-RW: This is a rewritable DVD which can be read by almost any standard DVD-ROM drive or DVD player. DVD-RW drives can also read and write to DVDs which are not rewritable. DVD-RWs have a storage capacity of 4.7 GB. The difference between these and DVD-RAMs is that they can also be played in standard DVD-ROM drives and standalone DVD players.
- DVD+RW: This is a rewritable DVD which can be read by almost any standard DVD-ROM drive or DVD player. DVD+RW drives can also read and write to DVDs which are not rewritable. DVD+RWs have a storage capacity of 4.7 GB. The difference between these and DVD-RAMs is that they can also be played in standard DVD-ROM drives and standalone DVD players.
- DVD-Video: DVD-Videos contain full-length feature films with high audio and video quality. The videos are encoded in MPEG-2 format.
Additional information:
- The UDF (Universal Disc Format) file system is used on DVDs. However the data can also be accessed via an ISO9660 data system which is also included on the DVD.
- DVD format no longer corresponds to any of the formats specified in the colored books.