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Blu-Ray Disk

What is Blu-ray Disc?
Blu-ray Disc (officially Abbreviated 'BD') is a optical disc medium designed to supersede the DVD. The physical medium is a 12 cm plastic optical disc, the same size as DVDs & CDs. Blu-Ray Discs can contain up to 25 GB of data per layer, with dual layer discs capacity of 50 GB.

The name Blu-ray Disc refers to the blue laser used to read the disc. With is being blue the wavelength is shorter allowing for greater desity than is possible with the longer-wavelength red laser used for DVDs. Blu-ray standard was developed by the Blu-ray Disc Association, a group representing makers of consumer electronics, computer hardware, and motion pictures.

The same physical size and appearance as CDs & DVDs, the BD operates using like principles. The data is written to or read from a rotating disc by means of a focused laser light beam.


Data rate
Theoretical Write time for Blu-ray Disc (minutes)

Drive speed
Mbit/s MB/s Single-Layer Dual-Layer
36 4.5 90 180
72 9 45 90
144 18 22.5 45
216 27 15 30
288 36 11.25 22.5
10× 360 45 9 18
12× 432 54 7.5 15


On-going development

On Jan. 1, 2010, Sony, in association with Panasonic, announced plans to increase the storage capacity on their Blu-ray Discs from 25GB to 33.4 GB via a technology called i-MLSE. The higher-capacity discs, according to Sony, will be readable on current Blu-ray Disc players with a firmware upgrade. No date has been set to include the increased space, but according to Blu-ray.com "it will likely happen sometime later this year."

On July 20, 2010, the research team of Sony and Japanese Tohoku University announced the joint development of a blue-violet laser, which will help in creating Blu-ray discs with a capacity of 1 TB (dual layer).