## constant angular velocity

(CAV) One of the two schemes for controlling the rate of rotation of the disk in a disk drive. Constant angular velocity keeps the rate of rotation constant. This means that the linear velocity of the disk under the head is larger when reading or writing the outer tracks. This in turn implies either a variation in the data rate to and from the heads or the bits per unit length along the track.

The alternative, constant linear velocity, requires the rate of rotation of the disk to accelerate and decelerate according to the radial postion of the heads, increasing the energy use and vibration.