Blu-ray Disc

Blu-ray, formally Blu-ray Disc, is a digital optical disc data storage format designed to supersede the DVD, capable of holding several hours of high-definition video. The format takes its name from the 405-nanometer blue-violet laser it uses to read and write data, a much shorter wavelength than the DVD's 650-nanometer red laser, letting a single-layer Blu-ray disc hold 25 gigabytes, about five times a same-size DVD's capacity, with dual-layer discs holding 50 gigabytes and later triple- and quadruple-layer BDXL discs reaching 100 and 128 gigabytes. Sony, developing the format through the industry-wide Blu-ray Disc Association, unveiled the first prototypes in October 2000 and released the first prototype player in Japan in April 2003, ahead of a worldwide commercial launch on June 20, 2006; Blu-ray then out-competed the rival HD DVD format, which Toshiba discontinued in February 2008.