Fujitsu Corporation

Kabushiki Kaisha Toshiba

Koichi Aikawa

Tatsuro Sasamoto

Akihide Jinzenji

Susumu Yoshida

Hideo Sado

Keiji Aruga

Tomoo Sukagawa

Toshitaka Matsunaga

Yoshiaki Koizumi

Yasuyoshi Asao

Tetsuya Tabuchi

According to one embodiment, a magnetic disk drive includes a disk, a first microactuator, a second microactuator and a servo controller. The disk comprises a first surface and a second surface. The first and second microactuators allow first and second heads associated with the first and second surfaces to make micromotion based on first and second operation amounts, respectively. The servo controller provides a third operation amount to the first microactuator as the first operation amount and provides an operation amount obtained by inverting a polarity of a frequency component with a particular frequency contained in the third operation amount, to the second microactuator as the second operation amount, if the third operation amount is generated as an operation amount to be provided to the first microactuator in a particular mode in which the first surface is used as a tracking surface.

Magnetic disk drive and method for controlling microactuator in magnetic disk drive

A disk device comprises a disk having predetermined information sectors recorded at a constant interval; a head scanning the disk; and a disturbance-compensation unit obtaining an amount of a disturbance based on a time-interval measurement in reading the predetermined information sectors so as to compensate a position of the head according to the amount of the disturbance.

Disk device conducting a disturbance compensation based on a time-interval measurement in reading servo sectors recorded on a disk

A disk drive unit includes acceleration sensors mounted thereon. A sequence for calculating an amount by which a head actuator is adjusted during recording and readout operations is changed based on an output from the acceleration sensors.

Disk drive unit and control method for same

A magnetic disk unit has two actuators each rotating on a common rotary shaft. The two actuators are driven by a voice coil motor. The voice coil motor comprises: a magnetic circuit comprising a magnet provided for the two actuators on a common basis and two yokes, which are associated with the two actuators, respectively, said two yokes being disposed at both sides between which the magnet intervenes; and two coils provided for the two actuators, respectively.

Storage device

Disclosed is a calibration method for an acceleration sensor in a storage device for calibrating and a storage device, an enclosure for calibrating the acceleration sensor for compensating a vibration of an enclosure in a state of its being mounted in a storage drive. The calibration method and mode comprises a step of exciting a actuator of the drive by flowing a drive current having a predetermined current value, a step of calculating the acceleration of the enclosure of the drive from the predetermined current value and a mechanical transfer function of the storage device, a step of detecting a measured value of the acceleration sensor, and a step of calculating a sensitivity of the acceleration sensor from the calculated acceleration and from the detected measured value. The acceleration sensor is calibrated in the state of its being mounted in the disk drive, and hence the sensitivity can be precisely calibrated.

Calibration method for acceleration sensor in storage device and storage device

Disclosed is a method of demodulating a position signal in a magnetic disk device for reading servo burst signals, which have been recorded in a servo area of a magnetic disk, by a head, and outputting a position signal, which indicates a deviation from a reference position on a track, using the servo burst signals that have been read. The position signal demodulating method includes (1) recording first and second servo burst signals in the servo area alternately in the radial direction, (2) digitally sampling the first and second servo burst signals, which have been read by the head, at a frequency two or more times greater than a servo burst signal frequency, (3) calculating area information of each of first and second servo burst signal waveforms by summing absolute values of the digitally sampled values in regard to each of the first and second servo burst signals, and (4) outputting, as a position signal, the difference between the area information of the first servo burst signal waveform and the area information of the second servo burst signal waveform.

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Kawasaki, Japan

Koichi Aikawa