US Patent 7944788 Optical disk drive

An optical disk drive capable of reproducing data even when defects, such as flaws or stains, are present in the disk. A system controller of an optical disk drive reproduces data by setting the maximum speed in accordance with the type of an optical disk, an amount of side-to-side runout, and the like. When reproduction of data becomes impracticable for reasons of meandering of a track, or the like, in the middle of reproduction of data, the rotational speed is decreased, and a retry is performed. However, when reproduction of data becomes impracticable for reasons of flaws or stains, the rotational speed is reversely increased, and a retry is performed.