US Patent 7376788 Optical disk drive

An optical disk drive which increases a read rate when a read command from a host system is input. Data read from the optical disk drive are buffered in cache memory, and requested data are subsequently transferred to a host system. The cache memory is divided into cache A and cache B. Directory data are chiefly buffered in the cache A, and file data are chiefly buffered in the cache B. A cache hit rate achieved when the directory data and the file data are alternately read is improved.