Toshiba has developed a Triple-Layer (Not only Double) HD-DVD ROM disc which has a capacity of 51GB. The Triple Layer HD-DVD-ROM can store up to 7 hours of High-Definition video. It has 3 layers with each layer has 17GB of capacity.
The new disc shares the same disc structure as standard DVD and previously announced HD DVD formats: two 0.6-mm thick discs bonded back-to-back. This time-tested physical structure offers proven volume manufacturing at little cost increment.