BD vs. DVD
Just as DVD meant a five to ten time increase in storage capacity compared to CD, Blu-ray Disc will increase DVD capacity by five to ten times. This is due, among other reasons, to the usage of a blue instead of a red laser and improved lens specifications, allowing for a much smaller focus laser beam which enables the recording of much smaller and higher density pits on the disc.
Due to the fact that the data layer on a Blu-ray Disc is placed much "closer" to the laser lens than in DVD (or even the HD-DVD proposal), there is less distortion resulting in significantly improved tolerances. Hence, more precision and ultra high storage densities are made possible.
As a result of Blu-ray Disc being manufactured as a single substrate disc comparable to CD, but unlike DVD (and the HD-DVD proposal), the manufacturing process does not involve the bonding of two substrates, resulting in less production material, a shorter production time and hence lower production costs per disc.
Blu-ray Disc has the same physical characteristics as DVD and CD, and like its predecessors, it also does not require a cartridge. This makes it possible to create Blu-ray Disc products that are backwards compatible with CD and DVD, allowing for a seamless transition to the new technology. Likewise, the technology is perfectly suitable for integration in small form factor equipment, like notebook computers.