What Is Blu-ray?

Blu-ray is an optical disc format whose specification was developed jointly by many of the world's leading electronic companies. It is intended act as a replacement for the DVD format, though manufacturers have promised that Blu-ray devices will remain backwards-compatible with DVDs. The name Blu-ray derives from the use of blue lasers to read the contents of the disc; DVD devices use larger-wavelength red lasers.

Blu-ray discs should be able to hold approximately five times as much data as DVDs and, like DVDs, will be available in both single-layer versions, with a data storage capacity of 25 gigabytes each, and dual-layer versions with double that.

The introduction of High Definition Television is said to have provided the commercial imperative behind the introduction of the Blu-Ray format. Its supporters claim that DVD simply lacks the storage capacity to provide acceptable picture quality on the new, higher-resolution screens.

The first Blu-ray devices became commercially available in 2006.