Constant angular velocity

Qualifier for the rated speed of an optical disc drive Comparison of several forms of disk storage showing tracks (not-to-scale); green denotes start and red denotes end. Note Apple 3.5–inch floppy disk drives used five speeds, increasing capacity by a fourth relative to simpler CAV drives.* Some CD-R(W) and DVD-R(W)/DVD+R(W) recorders operate in ZCLV, CAA or CAV modes. In optical storage, constant angular velocity (CAV) is a qualifier for the rated speed of any disc containing information, and may also be applied to the writing speed of recordable discs. A drive or disc operating in CAV mode maintains a constant angular velocity, contrasted with a constant linear velocity (CLV). A typical CD-ROM drive operates in CLV mode, in contrast to a floppy or hard disk drive, or gramophone, which operates in CAV mode. In CAV mode, the spindle motor turns at a constant speed, which makes the medium pass by the read/write head faster when the head is positioned at the outside of the disk. In contrast, in CLV mode, the spindle motor speed varies so that the medium passes by the head at the same speed regardless of where on the disk the head is positioned. If the disk is recorded at the same