Originally posted by: lordjedi
That's incorrect. The read/write times have to do with how fast the disc is spinning. And the reason BDs couldn't be made on existing lines is because they use a different laser (blue diode). HD-DVD actually use the same color laser, it's just narrower, but not as narrow as a blue laser. BDs are bigger in terms of space simply because they're using a blue laser diode instead of a red one, so they can get the beam smaller, which allows you to pack more data into the same area. HD-DVD is backware compatible because it uses a red laser, so the width just has to be changed between a DVD and an HD-DVD.
That's incorrect. The read/write times have to do with how fast the disc is spinning. And the reason BDs couldn't be made on existing lines is because they use a different laser (blue diode). HD-DVD actually use the same color laser, it's just narrower, but not as narrow as a blue laser. BDs are bigger in terms of space simply because they're using a blue laser diode instead of a red one, so they can get the beam smaller, which allows you to pack more data into the same area. HD-DVD is backware compatible because it uses a red laser, so the width just has to be changed between a DVD and an HD-DVD.
I think both HD DVD and Blu-ray use a 405nm blue laser.