Double-sided photo op may be used, but they are not easily accessed with a standard drive, as they require to be physically reverted to access the data on the other side.

This had led to optical drives—until recently—operating with a nonstop linear velocity (CLV). The spiral groove of the disc passed under its head at a Cassette to CD constant speed. Of advance the implication of CLV, as opposed to CAV, is that disc angular velocity is no lengthen constant, and spindle motor need to be designed to vary speed between 200 RPM on the outer rim and 500 RPM on the inner rim.