DVD: Digital Video Disc or Digital Versatile Disc
DVD stands for Digital Versatile Disc. It is commonly known as Digital Video Disc. It is a digital optical disc storage format used to store high capacity data like high quality videos and movies. It is also used to store operating system. It is invented and developed by 4 companies named Philips, Sony, Toshiba and Panasonic in 1995. DVDs provide higher storage capacity than CDs( compact disc) and can be played in multiple types of players like DVD players.
DVD Storage Capacity
On the basis of storage capacity, DVD can be divided in 4 types.
|1)||Single-sided, Single layer||4.7 gb|
|2)||Single-sided, Double layer||8.5 gb to 8.7 gb|
|3)||Double-sided, Single layer||9.4 gb|
|4)||Double-sided, Double layer||17.08 gb|
Physical measurements of a DVD
A DVD comes in two dimensions.
12 cm (120 mm): It is the most common size and generally used for storing software, movies, and operating system etc.
8 cm (80 mm): This size of DVDs are generally used for small devices like portable music player and video camera etc.
Initially, the DVD was developed as a substitute for VHS tapes, but soon they became popular as a data storage device. In 1972, audio CD was developed as a medium of entertainment. In 1993, two video disc formats were being developed, the Multimedia Compact Disc (MMCD) and the Super Density (SD) disc. In 1997, DVD took over CD as a medium of entertainment and data storage. Twister was the first movie put on DVD on 25 March, 1996.
On the basis of applications, a DVD can be categorized in different ways as described below:
- DVD-ROM: It can only be used for reading and cannot be written.
- DVD-R: It can be used to record any type of data.
- DVD-RW: It can be read, written, erased and rewritten.
- Large storage capacity, e.g. 4.7 to 9 Gb
- Excellent sound and picture quality, so best option to store videos and audios
- Relatively cheap as they are mass-produced
- Information can be stored on both sides of DVD unlike CD.