Hitachi has shown a prototype Blu-ray disc with a capacity of 100GB. The quad-layer platter, which offers more than ten times the storage of DVD, was shown at the recent CEATEC Expo in Japan. While super-high density BD discs have been promised before, the new Hitachi proposal is unique in that it will play on existing Blu-ray players after a firmware update. And it doesn’t end there. The company says that it is actively developing an eight-layer prototype, capable of 200GB of storage. While such capacities will be of limited interest to Hollywood studios, the potential for data back-up is immense.