Describe the operations of an optical disk drive used to read data from an optical disk, such as a CD or DVD.

Data is stored one a continuous spiraled track around the optical disk, the track is made up of a continuation of lands and pits, where lands will reflect the light focused onto them, and pits will scatter the light. The change in these pits and lands indicate a 1, while an unchanged continuation represents a 0. The reading is performed by a low-powered laser which is shone at the disk, the light is reflected back and measured to determine the pits and lands of the disk. The disk spins constantly with linear velocity.