Cambridge IGCSE Computer Science · Syllabus 0478 · Hardware
Optical Storage
What is Optical Storage?
Optical storage is secondary storage in which data is held as pits and lands along a spiral track on a disc, read by a laser that reflects differently from the two surfaces.
This definition is part of the Hardware chapter in Cambridge IGCSE Computer Science.
Optical Storage in context
Optical storage uses lasers to create and read pits and lands on the surface of a disc. A pit is a small indentation; a land is the flat surface between pits. When the laser shines on the surface, a pit and a land reflect the light differently, and the difference is interpreted as the binary values. The examples named by the syllabus are CD, DVD and Blu-ray.