What is the difference between blue ray and hd dvd?
The differences between HD DVD and Blu ray are basically comes down to storage and the way the discs are made, they both use a 405 nm blue-violet laser, with different Numerical apertures, HD DVD with a .65 and Blu ray with a .85, the point at which Blu ray reads the data is smaller so it allows more data per layer, this has a draw back though, it means the data layer is only .1mm away from the outer surface of the disc, where HD DVD is .6mm away from the disc surface, these means that the Blu disc must have a mandatory hard coding protective layer to prevent scratching. The specifications for players are also different. HD DVD requires on board memory, Ethernet connection, and a second video/audio decoding processor, where as Blu ray up until recently all of these have been optional, as of Nov 5th the secondary video/audio decoding processor and onboard memory is required for all newly designed players, no player has yet hit the market though, the Ethernet port is still optional. What
