DVD

 DVD-Digital Versatile Disc

                     DVD is an optical disc storage format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions.


DVD Formats :

There are several recordable DVD formats.

• DVD-R (often pronounced DVD-minus-R or DVD-dash-R) is a 4.7 gigabyte single-layer DVD that can be recorded to once. It cannot be written to in a DVD+R drive, although a DVD+R drive may or may not be able to play it back. Consumer DVD players will play these discs.
  
• DVD-RW is a rewritable version of DVD-R, and has the same size and restrictions on use.
• DVD-RAM is a special DVD format intended for computer use only. It uses a disc inside a special cartridge, and cannot be read or written in any other type of drive.
• DVD+R (often pronounced DVD-plus-R) is a one-time recordable format like DVD-R which uses a slightly different recording technology. You can't write a DVD+R disc in a DVD-R drive, but you can usually read or play a disc of either format in a player of the other format, and also in consumer DVD players.
• DVD+RW, despite the name, is more closely related in terms of technology to DVD-RW than DVD+R. It's an erasable, rewritable format.
• DVD+R DL is a dual-layer version of DVD+r and can hold roughly twice as much data (almost 9 gigabytes.)

Blu-ray Disc/HD DVD

               In 2006, two new formats called HD DVD and Blu-ray Disc were released as the successor to DVD. HD DVD competed unsuccessfully with Blu-ray Disc in the format war of 2006–2008. A dual layer HD DVD can store up to 30GB and a dual layer Blu-ray disc can hold up to 50GB