An optical disc standard finalized in February, 2002. The name is derived from the blue lasers that are used for reading and writing data.
The discs are the same sizes as DVDs, including both 8 cm and 12 cm versions. As with DVDs, Blu-ray discs have multiple recording layers, but the capacity of a single layer is 25 GB, approximately five-times that of DVD, which has a single-layer capacity of 4.7 GB. The high capacity of Blu-ray discs is commonly used for recording high-definition video.
