1 GENERATION: Compact Disc (CD) :- capacity 650/700MB Wave length of laser which reads data : 780nm Colour of laser : Red HISTORY
2 GENERATION: Digital Versatile Disc (DVD) :- capacity 4.7GB Wavelength of laser which reads data : 650nm Colour of laser : Red
3 GENERATION: Blu ray Disc (BD) :- capacity 25/50 GB wavelength of laser which reads data : 405 nm colour of laser : Blue- violet which was developed in 1996 by SHUJI NAKAMURA at NICHIA CORPORATION
THE NAME The Blu ray name is a combination of “ Blue ” for the colour of the laser is used and the “ ray ” for optical ray .
TYPES OF BD SINGLE LAYER: Can hold data upto 25/27 GB that means 2hrs of HD video or about 13hrs of standard video. DOUBLE LAYER: Can hold data upto 50GB that means 4.5hrs of HD video or more than 20hrs of standard video.
FORMATS OF BD
It comes in 4 different formats:
BD ROM (read only):- for reading recorded content.
BD – R (recordable):- for PC data storage.
BD – RW (rewritable):- for PC data storage.
BD – RE (rewritable):- for HDTV (High Definition Television) recording.
Hard coating technologies make Blu ray Disc most durable and family- friendly.
Hard coating technology provides resistance to:-
Much more ROBUST than today’s polycarbonate – based CD/DVD (and HD DVD’s)
It uses Data Encryption Standard (DES) that has a key length of 56bits.
A key block and disc ID are written into the ROM area to prevent illegal copying.
BDA :(Blu ray Disc Association) This association develops and licences Blu ray Disc technology. (in 2002)
Blu ray Movies
FEATURES OF BD:
With BD we can :-
Record HDTV without any quality loss.
Instantly skip to any spot on disc.
Record on one program while watching other on the disc.
Create play list.
Automatically search for an empty space on the
disc to avoid recording over a program.
PRESENTED BY: CHRISTINE JOSE K MCA Department Vidya Academy of Science and Techonology Thalakkottukara P.O, Thrissur, Kerala, India, Pin:680 501.