International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Hiromi Nishimiya

Akira Kibashi

Hiroaki Suzuki

Takahiro Saito

Hideo Asano

Kenji Kuroki

Kenji Okada

Hiroshi Uchiike

Atsushi Kanamaru

Hideki Ohzeki

Takashi Kuroda

Toshio Kakihara

Makoto Takase

Takao Matsui

Tatsuya Endo

Koji Kurachi

Takahiro Saitoh

Katsumi Suda

Tomoyuki Oyama

Akinori Yuba

A method for an error recovery process in a disk-drive device. The method includes starting the error recovery process in response to an error which has occurred in a process corresponding to a command from a host to access a disk. The method also includes receiving a new read command from the host during the error recovery process. In addition, the method includes interrupting the error recovery process in accordance with preset conditions and reading out data from the disk at an address designated by the read command. Furthermore, the method includes transferring the read-out data to the host.

Disk-drive device and method for error recovery thereof

An executable command selection system and method are provided. A command is selected as the next-to-be-executed command when the execution waiting time for the command is less than or equal to a predetermined reference time. In addition, the command selected as the next-to-be-executed command has an execution waiting time greater than or equal to a scanning time. Once a command is selected as the next-to-be-executed command, calculation of execution waiting times for subsequent commands in the command queue stops. In this manner, when the number of commands in the command queue exceeds a predetermined number, the method of the present invention improves the efficiency of command execution for a storage device.

Data storage unit, executable command selection method, and data processing method

The present invention includes a method of reading and writing data on a recording medium, and a system including a disk drive apparatus and a disk drive apparatus controller. According to the method of the present invention, data can be read in the middle of a plurality of write commands provided that the addresses of the read/write data locations do not overlap. This method and system results in improved read/write times.

Method and system of reading and writing data by a disk drive apparatus

A method and apparatus for recovering from operation errors arising in an information recording and reproducing unit using a head with a GMR sensor is described. The read and write operations of the unit comprise executing a first error recovery procedure for recovering the operation error, executing a first GMR evaluation procedure for evaluating the performance of the GMR sensor when the operation error cannot be recovered by the first error recovery procedure, and applying a resetting pulse to the GMR sensor in accordance with the first GMR evaluation procedure.

Error recovery in unit using GMR sensor

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

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Yamato, Japan

Hiromi Nishimiya