Optical disc drive beam on a smaller spot size and to read smaller pits. DVD lens supports a different focus for CD or DVD media with same laser. With the newer Blu-ray disc drives, the laser only has to penetrate 0.1 mm of material. Thus the optical assembly would normally have to have an even greater focus range. In practice, the Blu-ray optical system is separate from the DVD/CD system. During the times of CD writer drives, they are often marked with three different speed ratings. In these cases, the first speed is for write-once (R) operations, the second speed for re-write (RW)
Finalize (optical discs) Finalize (optical discs) Finalizing (also spelled finalising) an optical disc is the process of writing out support data such as DVD menus, directory data, and the like to an optical disc in order to make it playable on a system other than the one it was recorded on. As a general rule, finalization means that the disc cannot have any additional data written to it. It is the last step in the DVD authoring process. The term is also used as an alternative word for the "closing" of a CD-R, in which Table of Contents data and the like are