Disk drive having control mechanism to reduce or eliminate redundant write operations and the method thereof

Abstract

A disk drive and a control method thereof to reduce the number of write operations to a medium while minimizing command overhead time. A disk drive,comprises a hard disk controller (HDC),, a cache memory,, and a host interface controller (HIC),with a command queue for retaining a plurality of commands which are cached in cache memory,. The HIC,performs the periphery interface processing by hardware. The disk drive,further comprises a local microprocessor unit (MPU),for controlling the overall operation of HDD,, including operations of HDC,and HIC,. The local MPU,instructs the HIC,to write data to a medium by write commands cached in the cache memory,. When local MPU,retrieves a command from a plurality of write commands cached in cache memory,which is completely overwritten by a command more recently issued, a write operation to the medium is not performed by the retrieved command.