Hitachi Global Storage Technologies Japan, Ltd.

Hitachi, Ltd.

Kei Yasuna

Takashi Yamaguchi

Kenichiro Sugiyama

Keiko Watanabe

Tetsuya Hamaguchi

Marutomo Goto

Makoto Horisaki

Naoki Satoh

Hidehiko Numasato

Tsuyoshi Arai

Kazuaki Usui

Yohichi Kusagaya

A magnetic disk apparatus capable of generating a reference clock signal without using an external reference by writing a clock track only once using a head of the magnetic disk apparatus even if the head is of a read/write element separation type. Using the head of the magnetic disk apparatus, a clock track is recorded only once and the recorded clock track is played back to measure the total number of clock bits in one revolution. A time interval between servo sectors is determined by dividing the total number of clock bits thus measured by the number of servo sectors. By using as a timing reference the clock bits produced by playing back the clock track, the servo sectors are recorded in such a manner that they are located at the determined interval.

Magnetic disk apparatus and servo signal recording method

A magnetic disk apparatus and a servo pattern recording method therefor, enabling writing of servo signal with high quality, without being affected with ill influences due to fluctuation on a rotation speed when conducting the self servo write operation, comprises: a magnetic disk; a headhaving a write element for use of recording information onto the magnetic disk and a read element for reproducing information from the magnetic disk; and an actuator for moving said head to a desired radial position on the magnetic disk, wherein on the magnetic disk is recorded servo patternsfor positioning the head on a recording surface thereof, and within each of the servo patterns are recorded, a pattern sector markeras a marker for detecting passage time of the head, a track ID code, and a burst patternfor use of detection of the radial position of the head, following a preamblefor use of synchronization of time-base circuit, and further recorded and disposed a second preambleand a second sector markercontinuously.

Magnetic disk apparatus and servo pattern recording method therefor

Servo-write arrangements to self-record servo signals onto magnetic disk arrangements.

Magnetic disk device and servo write method

A servo write method capable of generating and recording correction data, to be used for compensating for repeatable position error caused by write errors of servo patterns, in a short time is presented. In the recording of the servo pattern, correction data for correcting revolution-synchronous components are generated from a position error signal which is obtained from the difference between a target position and a magnetic head position, and the correction data are recorded in servo areas on a disk.

Servo pattern recording method

A magnetic disk apparatus includes an actuator for moving a head to a position above the magnetic disk in a servo track movement operation, a range limiter for limiting a movable range of the actuator, a range specifier for setting a specific range of the actuator in the movable range of the actuator, and a control unit. The control unit enables writing a servo signal into the specific range at servo track movement pitch based on servo tracks recorded with the servo signal, correcting the servo track movement pitch on the basis of the number of servo tracks in the specific range and executing control to write the servo signal at corrected servo track movement pitch.

Magnetic disk apparatus and its servo signal recording method

The magnetic disk apparatus includes a magnetic disk for storing thereinto information; a head equipped with a recording conversion element for writing information into the magnetic disk and a reproducing conversion element for reading information from the magnetic disk; an actuator arranged by a suspension for supporting the head so as to move the head on the magnetic disk, and also a drive apparatus for driving the suspension; and a stopper for limiting a movable range of the actuator, whereby a distance between a reproduction element and a recording element is measured and also a track width of the magnetic disk is measured in order to execute a self-servo write operation.

Under existence of an impact and a vibration, a throughput and a reliability of a recording and reproducing operation in a magnetic disc apparatus are reduced. Accordingly, a mechanism for fixing a coarse moving actuator at an optional position is provided, at a time of following to a track, a motion of the coarse moving actuator is restricted and a positioning is performed by a fine moving actuator. Even when a vibration and an impact is applied from an external portion during the track following operation, it is possible to prevent the head position from being shifted and it is possible to perform a recording and reproducing operation. Further, it is possible to prevent adjacent data from being erroneously broken.

Magnetic disc apparatus having actuator for head positioning mechanism

An acceleration detecting apparatus for a magnetic disk apparatus capable of detecting with high reliability the disturbances such as rotational and translational shocks and vibrations applied externally to the magnetic disk apparatus to thereby prevent destruction or the like damages of data recorded on a disk of the magnetic disk apparatus upon occurrence of off-track event under the influence of the disturbance. The apparatus includes a pair of acceleration detectors for detecting acceleration in two directions extending discretely in parallel to each other. The acceleration detectors are disposed at positions closer to the magnetic disk relative to a pivot shaft for a head supporting arm as viewed in a longitudinal direction of an oblong box-like casing of the magnetic disk apparatus in a plane which forms an angle not greater than 10 degrees relative to the plane of the magnetic disk. By employing the angular acceleration detectors in combination with an angular velocity detector, the rotational disturbances due to rotational shock/vibration can be detected with much enhanced reliability, and destruction of the data recorded on the magnetic disk due to the off-track read/write operation can positively be prevented.

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Chiyoda, Japan

Kei Yasuna