Blu-ray is the name of a new generation of high definition (HD) optical disc format. The format is capable of recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. A Blu-ray disc offers more than five times the storage capacity of traditional DVDs with up to 25GB on a single-layer disc and 50GB on a dual-layer disc. The name Blu-ray is derived from the underlying technology, which utilises a blue-violet laser to read and write data.