International Business Machines Corporation

Masaomi Ikeda

Hiroaki Suzuki

Hideo Asano

Takao Matsui

Kaoru Umemura

Michio Nakajima

Masashi Murai

Tatsuya Endoh

Akira Shibata

Junji Hashimoto

Yumi Nagano

A method for controlling write current to a write head during data write on a hard disk drive is disclosed. A direct access storage device includes a rotating storage medium in which data are magnetically written, a write head for writing data in the rotating storage medium, and a write current control circuit for changing write current-value settings to be supplied to the write head according to a predetermined elapsed time from the beginning of a write operation.

Method for controlling write current to a write head during data write on a hard disk

An RW offset setting method which includes recording a test pattern by a write head, reading the test pattern by a read head, measuring an amplitude of a read back signal at each tracking position, finding an approximate expression of a profile of the measured amplitude, finding a tracking position, and finding a RW offset based on this tracking position, setting a RW offset for all tracks in the disk device based on the RW offsets about the plurality of tracks to be measured. A read data error recovery method that includes the steps of determining an off-track direction where the amplitude increases, searching an off-track position where the amplitude becomes a local maximum, measuring the amplitude at each off-track position reading data recorded in the data sector.

System and method for setting a read/write offset and for recovering from data read errors

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Rochester, MN, United States of America

Masaomi Ikeda