International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Kenji Ogasawara

Isao Yoneda

Hiroshi Uchiike

Nobuyuki Kitazaki

Fuminori Sai

Hiroshi Yanagisawa

Koji Kurachi

Takashi Nakamura

Shinji Ueno

Yuji Yokoe

Masahiro Shimizu

Nobuya Matsubara

Takao Matsui

Masaomi Ikeda

Yuji Kigami

Hirofumi Yanase

Kazushi Tsuwako

Tsutomu Numata

Michio Nakajima

Katsumi Suda

Fujio Harako

Masaharu Kawamura

Hiroaki Suzuki

Takashi Sugawara

Keishi Takahashi

Yuzo Nakagawa

Takashi Kuroda

Hirofumi Saitoh

Yutaka Ozawa

Keiji Kobayashi

Atsushi Tobari

Yoshiro Amano

Atsushi Takeichi

Koichi Sato

Shusuke Kurihara

Kaoru Iseri

Shuhsuke Kurihara

Yuhji Takagi

Yoshihiko Aoki

Mayumi Okada

Kenichiroh Satoh

Kazunari Tsuchimto

Embodiments of the invention provide a disk device and a method of controlling the device which is capable of suppressing peak current, even for serial communication, that is required when initiating rotation of a spindle motor down to a level equivalent to that of parallel communication, without prolonging elapsed time before reaching the steady rotation speed. In one embodiment, an HDD includes a serial communication circuit which executes serial communication with a host, an SPM which rotates a disk, an HDC/MPU which controls the SPM and the serial communication circuit. The HDC/MPU, after shutting down the serial communication circuit once, starts up the serial communication circuit again when rotation speed of the SPM reached the specified standard value, and establishes serial communication with the host by means of the serial communication circuit.

Disk device for serial communication and method of controlling the same

The data possessed by a parent hard disk drive is exported to a baby hard disk drive, which is connected to the parent hard disk drive, and thus, the baby hard disk drive executes by itself an optimization/inspection process including writing of servo information. A hard disk drive is reproduced by incorporating 'DNA' used for reproduction into each hard disk drive, and then, by performing self-optimization and/or self-inspection by a new hard disk drive (baby hard disk drive), according to information supplied by a finished hard disk drive (parent hard disk drive).

Systems and methods for hard disk drive optimization and manufacturing

Embodiments of the invention provide techniques to inspect the track pitch of a magnetic disk. In one embodiment, the track pitch is inspected using the servo information that was written onto the magnetic disk. A PES gain is set to be PGA head is moved to a position K near the position where control is to switch between MPES and SPES, and then MPES and SPES are calculated using reproduced burst signals and PGThe quantity of change in the inspection HSP which is a half-servo pitch of an inspection-related burst pattern, with respect to an ideal half-servo pitch, is detected by calculating PES&#x394;, the difference between the MPES and SPES at position K. The track pitch is thus judged whether it is abnormal.

Method for inspecting track pitch in a magnetic disk

The read/write offset between the read head and write head is used to determine the head width ratio between the read head width and write head width. The servo information is written onto the magnetic disk in accordance with the APC value and track pitch that are derived from the determined head with ratio.

Servo information write method, data storage device, and programs

Disclosed is a data storage device to provide servo patterns of a track pitch individually consistent with head characteristics (writing width, and reading width) in a recording medium of a hard disk device. The data storage device is provided with a disk having pitch information indicating a track pitch recorded in a predetermined area, and a head for scanning the disk to read the TPI ID and reading/writing data from/in the disk by being subjected to seeking control based on the TPI ID. The TPI ID is recorded as a part of a servo pattern in a TPI ID embedded area provided in an outer periphery of a data area of the disk.

Data storage device, recording medium, servo writing method, and data reading/writing method

A servo system wherein a read head R detects a servo pattern that is written on a magnetic disk by a write head W. Position control of the write head W is exercised in accordance with the detected servo pattern, and the read head R detects a propagation pattern that is written on the magnetic disk by the write head W. Position of the write head W is corrected in accordance with the detected propagation pattern.

Servo information write method, servo control method, data storage device, and program

A position control system for a magnetic head improves servo tracking characteristics in a low frequency range without impairing the stability of seek operations. The position control system is equipped with two integrators: a first integratorand second integratorThe gain K' of the second integratoris set larger than the gain Kof the first integratorThe first integratorplays the role of offsetting the bias force acting on the magnetic head while the second integratorplays the role of improving the servo tracking characteristics in the low frequency range.

Disk drive apparatus, head position control method, and hard disk drive

A method to enable servo information to be detected surely and stably even when a time interval between servo sectors is changed due to disk shifting. A time interval TS(i) is calculated according to an internal variable value, which is in proportion to a displacement &Dgr;r(i) of a servo area SF(i) in a radial direction of a subject disk (step S6). The displacement &Dgr;r(i) is calculated from already detected servo information&lsqb;, thereby&rsqb;. Thereby, a time interval for detecting servo information is adjusted according to the above described time interval TS(i) (steps S7 and S4). The time interval TS(i) is the time interval between passing of a servo sector in the servo area SF(i) under the head H and passing of a servo sector in the servo area SF(i&plus;1) under the head H.

Method for controlling servo information detection timing and rotational speed of disk, and disk drive

The present invention solves a problem that useless or wasted space exists on a data recording disk between read/write heads of narrower head width than others in the case that an uniform track pitch is used, and a head width of each head varies due to a fabrication tolerance. A data recording disk of the present invention comprises a first data recording surface and a second data recording surface, and a track pitch of adjacent data recording tracks of the first data recording surface differs from a track pitch of adjacent data recording tracks of the second data recording surface. All data recording tracks of the first data recording surface have substantially the same track width, and all gaps of the first data recording surface have substantially the same gap width, and, all data recording tracks of the second data recording surface have substantially the same track width, and all gaps of the second data recording surface have substantially the same gap width.

Data recording disk and disk drive device for reducing wasted space on a data recording disk

A disk drive with means to prevent accidental landing of a head/slider on the disk surface is described. In one embodiment a shock sensor is provided to sense external shocks received by the mechanism. During loading (positioning) of the actuator bearing the head/slider over the disk, if a shock is sensed, loading is stopped and an immediate unloading is performed to return the actuator to the withdrawn position. In another embodiment the unload operation is performed when the rotational speed of the disk is changed. In another embodiment the unload operation is performed when the rotational speed of the disk drops below a threshold. A circuit and method for detecting when the rotational speed of the disk drops below a threshold is also provided. The unloading in the various embodiments may be performed using velocity control or without velocity control.

Disk drive with actuator load/unload controller

The present invention provides a disk drive, a loading/unloading apparatus, and a method for controlling the apparatus, capable of improving the reliability of data by performing stable speed control. A disk drive comprises a VCM spindle driver for rotating a disk, a magnetic head, an actuator mechanism for moving a head slider having the magnetic head to a position above the surface of the magnetic disk and an unloaded position, a ramp block, and a CPU/HDC for performing the speed control of an actuator and the calibration control for detecting the offset and dynamic range of an AD converter before the speed control and controlling the operation for reading or writing data from or into the disk, which increases a rectangular current value to be applied to a voice coil while successively changing codes, measures an offset in accordance with the AD converter value for each current value, and moreover measures a dynamic range by deciding a nonlinear area when the difference between the expected value and measured value of the AD converter becomes a predetermined value or more.

Disk drive loading/unloading apparatus and method for controlling the apparatus

The invention relates to a head mechanism control apparatus for magnetic recording device which ensures that the transducer head has been unloaded in a head unloading operation. A head slider having a transducer head is mounted on a head arm and is unloaded from the disk by the swinging of the head arm. The retract position is at the limit portion of the swingable range of the head arm. When the head slider is successfully unloaded to the retract position, a drive force applied to the head arm in the unload direction causes little movement of the head arm. After an unloading is performed, a position check drive force is applied to the head arm and the moving speed of the head slider is detected. Based on the moving speed, it is judged whether the head slider has been unloaded to the retract position. If the head slider has not been unloaded to the retract position, re-unloading is performed for moving the head slider to the retract position.

Head mechanism control apparatus, disk drive, and head unload control

A magnetoresistive (MR) reproduction element is positioned during data recording, data reproduction, and formatting so that its total range of movement is 3/2 times a range of movement (microjogging) from the location of the reproduction element in data recording to the location of the reproduction element in data reproduction. The total range of movement is centered within a range where the detection of positional error of the reproduction element changes linearly. Therefore, in the respective data recording, data reproduction and formatting processes, microjogging is performed and the detection of positional error changes linearly for each of an off-track OF.sub.W in data recording, an off-track OF.sub.R in data reproduction, and an off-track OF.sub.F in formatting. Accordingly, the characteristics of the MR reproduction element can be effectively used to a maximum degree and information can be reproduced without being undetected or erroneously detected.

Magnetoresistive head and hard drive system having offsets from center

A method and apparatus for accurately positioning the magnetic head of disk drives is disclosed. A recording medium is provided having two radial data structures formed thereon. Each radial data structure includes two parallel and adjacent data burst pattern trains. The first burst pattern is defined by a first side centrally aligned with a concentric data track and a second side opposed to the first side and centrally aligned with an adjacent concentric data track. The third burst pattern is defined by a third side spaced apart from the first side of the first burst pattern by a distance not greater than the read width of a magnetic head and a fourth side opposed to the third side and spaced apart from the second side by a distance not greater than the read width. The first radial data structure generates a first signal for positioning the magnetic head relative to the recording medium. The second radial data structure, parallel and offset from the first data structure, generates a second head position signal. Thus, the second head position signal is detected before the first head position signal becomes undetectable.

Magnetic recording medium magnetic head positioning method, and magnetic

A mechanism for compensating the servo data in a disk storage drive is provided. On each recording surface of a disk, a plurality of servo regions are diametrally formed in data regions along the diametral direction of the disk. In the servo region, a gray code (cyclic binary code) representing the address of a data track is recorded so as to correspond to the data track, and a burst pattern as a signal for positioning the head on the track are recorded. In the data track region, tracks are formed at a predetermined pitch P and in the tracks, a plurality of data is recorded. ID (Identification) is the identification information of the individual data. A servo compensation signal region is formed at a position sandwiched by the data region and the servo region known as the write recovery area. This is to compensate the servo signal in the servo region, thereby to enable error recovery when a read error or the like occurs in the servo region.

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Fujisawa, Japan

Kenji Ogasawara