Phase change medium erasable at low speed and recordable at high speed and a driving device for such a medium

摘要

A phase change medium, a device and a method for driving a phase change medium are proposed that allow writing at high speed and erasing at low speed. The proposed low-speed erasing option must be seen as a formatting option that can be applied to the whole medium (or to part of the medium) so as to put the medium (or part of the medium) back to a virgin state. With the invention, direct overwriting of data is not possible: the data have first to be erased at low speed before new data can be written on the medium at high speed. According to the invention, the medium is rotated at a linear velocity that depends on the selected operating mode, the linear velocity applied in the writing mode being much higher than said maximum crystalline velocity, and the linear velocity applied in said erasing mode being equal to or lower than said maximum crystalline velocity. Application: DVD+R high-speed.