International Business Machines Corporation

Takahiro Saitoh

Hideki Ohzeki

Akira Kibashi

Kenji Okada

Atsushi Kanamaru

Toshio Kakihara

Hiromi Nishimiya

Yuhji Kigami

A disk device and a method are described for reassigning data areas (e.g. sectors) which minimize the reduction in the data transfer rate when alternate data areas are used to replace defective areas. The disk device uses a plurality of data zones with spare areas allocated in each data zone. An alternate area is allocated (a) in the spare area within the data zone where the error occurs and (b) at an angular position offset more than a predetermined angle from a position of the data in which the error occurs. The offset angle allows the device time to seek to the alternate area, read the alternate area and seek back to the area following the defective area within a single rotation of the disk.

Disk device and data reassignment method

A storage device is described which has a plurality of different error recovery routines which are are divided into groups. When an error occurs, specific routines are selected from the groups in accordance with the error type. The selected routines are executed in order. By preferentially executing the selected routines corresponding to the error type, the error recovery rate in the early stages of the error recovery procedure is enhanced.

Storage device and error recovery method executing a plurality of error

A disk drive and a method for controlling the disk drive in which an additional read from a medium can be performed as needed while minimizing the command overhead to the minimum. In a disk drive device 10, even if a read command is issued, and all the required data is stored in the cache memory such that the data transfer can be performed without the intervention of a local MPU 16, a HIC 15 performs the data transfer so as to leave the last one block and waits for the intervention of the local MPU 16. The local MPU 16 provides instructions to transfer the last one block when the preparation for the command termination is completed, and if a plurality of blocks of data to be transferred are remaining when the local MPU 16 instructs the HIC 15 to transfer the last one block, the HIC 15 executes all the data transfer without stopping the data transfer before the last one block, completing the command.

Disk drive device and method for controlling the same

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Yokohama, Japan

Takahiro Saitoh