DVD
From ArticleWorld
DVDs appear to be the same as CDs yet can contain over ten times more raw data and are more secure for security purposes.
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DVD’s Short History
In the early 1990’s a number of premiere companies were finding a newer means of storing information and media devices. There many mediums to the course of the DVD, two of which of course were the CD and the Laserdisc. The Laserdisc was short lived and quickly replaced with the single layered DVD that could store up to 4.7 Gigabytes of data.
Single layer and double layer
Single layered DVD were capable of storing only 4.7 Gig of data whereas the double layer or double density is capable of having compressed data so that twice the capacity of data can be stored. This is idea considering that most modern movies are typically around 8 to 9.3 Gig in size.
Encryption and Region Keys
All DVDs are encrypted with a unique eight bit encryption layout. One letter space equals a bit. These eight bit layouts are set up in a series of possible combinations that are tied to Region Keys. These Region Keys are utilized in certain parts of the world, depending on the Key. There is one that is focused for the North American continent, for example. There are a total of 8 keys that are in use, technically key code 7 is reserved.
These keys are for only movie and certain medias though.
Games and game consoles
The Playstation used compact discs as its game sources and even though they were encrypted and compressed they were highly limited when the Playstation 2 and Xbox came out. Both went the way of the DVD, using unique encryption methods and compression to utilize the full capabilities of the DVDs for higher resolution, flow, and playability.
Audio and data
DVDs are also ideal for data storage and to a minor extent for audio, although this is still in the works as there are no DVD players in vehicles and the DVD plays that are portable are somewhat in cumbersome. The audio aspect of this has been sapped due to the popularity of iPods and related mediums.