Constant angular velocity

Constant Angular Velocity (CAV) refers to how information is written to or read from a rotating data disk. A typical example can be seen in one of the differences between an LP Record and a Compact Audio Disc (CD). With an LP, the disc always spins at the same rate (CAV), so the surface of the record passes the needle at slower linar rate as the needle moves toward the center of the disc. Whereas, with a CD, the motor speed decreases as the read head moves away from the center to keep disc moving past the read head at a constant linear velocity (CLV).