HD-DVD

HD-DVD (High definition digital versatile disk) was launched by NEC and Toshiba and is physically similar to an ordinary DVD (thickness 0.6 mm for the substrate and the protective coating) except that it uses a blue laser.

It has a capacity of 15 GB per face and per layer for read-only media, and 20 GB for rewritable disks. By offering a physical structure close to that of the DVD, NEC and Toshiba were aiming for a seamless transition from one technology to the other between 2005 and 2010.