Repairing and Upgrading Your PC

Optical Disc Types

All mainstream optical discs, from the oldest CDs to the most recent high-capacity DVDs, are based on the original CD specification. The dimensions of a standard CD or DVD are 120 mm in diameter (60 mm radius) by 1.2 mm thick, with a 15 mm diameter central hole that accommodates the rotating center spindle of the drive.

Commercial CDs and DVDs are produced by a physical stamping process, and are referred to as pressed discs or stamped discs. Commercial discs may be one-sided or two-sided, and the data side or sides are nearly always a reflective silver color. Writable discs are produced by the operation of a relatively high power laser on a layer of dye or another substance that can be altered by light, and are always one-sided. ...