Fujitsu Corporation

Toshiba Storage Device Corporation

Yukio Abe

Shigenori Yanagi

Takeshi Hara

Mitsuo Kamimura

Atsushi Suzuki

Satoshi Yamashita

Shunji Saitoh

Takehiko Tsuboi

Shunji Saitou

Koji Ikenoya

Hiroyuki Kobayashi

Takahiro Aoki

Hiroshi Isokawa

Koji Ishii

Yoshinari Higashino

Takao Abe

Yoshifumi Obara

Kunihiro Shimada

Toshihiko Matsuda

Kiyoshi Sakuma

Kentaroh Katoh

Tomoo Furukawa

Tsuyoshi Takahashi

Fumiya Kudo

Syunji Saitou

A heater for changing a projection distance protrusion value by thermal expansion accompanying electric-power-distributed heating is provided in a head having at least a reading element. At desired correction timing, a changed distance detection unit measures a clearance changed distance in a state in which the head is positioned to a track on the recording medium while increasing the amount of electric power distributed to the heater. A contact determination unit determines that the head is brought into contact with the recording medium when a derivative value of the clearance changed distance is below a predetermined threshold value. A measurement output unit outputs the clearance changed distance detected by the changed distance detection unit at the time of contact determination of the contact determination unit as a measurement result of the clearance between the reading element and the recording medium.

Storage device, control method, control device, and program

A storage device receives and holds a storage medium that is subjected to first servo writing processing for writing servo information, a Gray code of which is offset, from an inner cylinder or an outer cylinder to a predetermined cylinder and, after the first servo writing processing, subjected to second servo writing processing for writing servo information from an opposite direction to the predetermined cylinder and in which Gray codes are written to be offset not to overlap in the first or second servo writing processing and the pieces of servo information having different mark patterns are written in the first servo writing processing and the second servo writing processing. The storage device acquires cylinder information and mark patterns from the servo information written in the held storage medium and controls a position of a head based on the acquired cylinder information and mark patterns.

Storage device and servo information writing method

A rewrite determining unit acquires, for every servo frame recorded on a magnetic disk, an amplification degree, i.e., a gain of an amplifier circuit by which a read signal read from the magnetic disk is amplified to a predetermined output, determines a rewrite sector count based on the amplification degree, and performs data rewriting according to the rewrite sector count.

Control apparatus, storage apparatus, and computer product

A rewrite determining unit of a hard disk apparatus acquires a servo signal that includes an offtrack amount corresponding to each servo frame from a position information memory, and determines whether a write fault has occurred based on the servo signal. If a write fault has occurred, the rewrite determining unit determines a rewrite sector count, and a write controller controls a hard disk controller so that rewriting is performed to correspond to the rewrite sector count determined by the rewrite determining unit.

A head control device for controlling, through thermal expansion of a heater, a position of a head for reading and writing data from and to a storage medium, includes a heater control unit that increases a current supplied to the heater stepwise; and an external-force sample retrieving unit that retrieves sampling values of signals each indicating a magnitude of an external force acting on the head in a moving direction of a head support mechanism. The head control device also includes an external-force evaluating unit that calculates a representative value of the sampling values retrieved by the external-force sample retrieving unit to evaluate the magnitude of the external force every time the heater control unit increases the current; and a contact detecting unit that detects contact between the head and the storage medium by comparing each evaluation result by the external-force evaluating unit with a predetermined threshold value.

Head control device, storage device, and contact detection method

A control apparatus detects positional information of a head performing writing processing every predetermined time interval, and computes next-sample projected positional information of the head based on the difference between the positional information detected the previous time and the positional information detected the current time, and the current detected positional information for every position information detected. The control apparatus determines whether the computed next-sample projected positional information is greater than a next-sample projected position threshold which is a predetermined threshold. Following this, in the case that determination is made that the next-sample projected positional information is greater than the projected position threshold, the disk control apparatus controls a storage device to stop the writing processing after the writing processing is performed through the end of the sector wherein the writing processing is currently being performed.

Control apparatus, storage apparatus, and writing control method

When a head is subjected to external vibration while a controller is controlling the head according to a positioning-oriented controller characteristic, the positioning-oriented controller characteristic are changed to a vibration-reducing controller characteristic. Moreover, when the external vibration stop while the controller is controlling the head according to the vibration-reducing controller characteristic, the vibration-reducing controller characteristic are changed to the positioning-oriented controller characteristic.

Controller-characteristic changing apparatus, storage device, controller-characteristic changing method, and computer product

A retraction control unit controls a retraction of a head of a storage device to a retraction position apart from a ramp by a predetermined distance. When the head is retracted from the retraction position to the ramp, a speed control unit controls a speed of the head to ascend the ramp to be constant by outputting a preset control signal.

Control apparatus, storage device, and head retracting method

An amplitude measurement unit measures an amplitude of a read signal from a preamble unit in a servo area of a predetermined frame number m per one rotation of the recording medium for a predetermined cycle number n while increasing an electric power amount distributed to the heater in the state in which the head is positioned to a track on the recording medium, and a mean amplitude calculating unit calculates a mean amplitude from an amplitude measurement value which is measured by the number which is the frame number m multiplied by the cycle number n. A contact determination unit calculates a mean amplitude variation amount per a unit heater electric power amount as a contact determination value, and determines that the head is in contact with the recording medium when the contact determination value is lower than a predetermined threshold value, and a flying height calculating unit which calculates a flying height of the head with respect to the surface of the recording medium from the heater electric power amount at the point when contact is determined.

Storage apparatus, control method, control device, and program which can control flying height of head accurate

Offtrack amounts corresponding to every servo in which data writing has been completed is stored in a storage unit. Offtrack amount corresponding to a next servo frame, which is a servo frame present next to a servo frame for which data has been written, is calculated from the offtrack amounts stored in the storage unit. Based on the offtrack amount of the next servo frame, it is decided whether data needs to be rewritten in a sector present before the next servo frame.

A heater for changing a projection distance protrusion value by thermal expansion accompanying electric-power-distributed heating is embedded in a head having a reading element and a recording element. A clearance control information measurement unit measures and saves, at desired correction timing, clearance control information including a clearance required for controlling the clearance between the reading element and the recording medium, heater projection sensitivity protrusion sensitivity, projection distance protrusion value transition time, recording current projection distance protrusion value, and a temperature correction coefficient. The clearance control unit varies the electric power distributed to the heater and changes the projection distance protrusion value of the head, thereby controlling the clearance to a target clearance upon reproduction and recording.

Storage device, control device, control method, and program

A head-slap detecting device detects a head slap. The head slap causes a storage medium to be slapped by at least one storage-medium driving unit that performs at least one of reproduction and recording of data from and to the storage medium. The head-slap detecting device includes a detecting unit that detects the head slap by determining whether a first variable gain obtained from a variable gain amplifier that amplifies an output of data reproduced by the storage-medium driving unit exceeds a predetermined threshold.

Head slap detecting device, storage device, head slap detecting method, and computer product

A disk control apparatus controls a disk driving unit that performs read/write of data with a head. A vibration detecting unit detects a vibration of the disk driving unit. A disk control unit controls the disk driving unit based on the detected vibration.

Disk control apparatus, disk control method, and computer product

A storage device, which comprises a storage media, a spindle motor which spins the storage media, a head unit which records and reads the data to the storage media, an actuator which carries out the positioning operation to the head unit on the storage media, a loading and unloading system which controls the actuator and carries out the unload operation that withdraws the head unit from the storage media and the loading operation that shifts the head unit onto the storage media, and a measurement means which measures the unloading energy required for the unload operation.

Storage device and its control method and manufacturing method

A magnetic disk apparatus includes a magnetic disk with normal and double servo sectors arranged alternately. If a servo interruption period corresponding to adjacent first servo sectors is a first servo interruption period, then a second servo interruption period that is a servo interruption period corresponding to adjacent first servo sector and second servo sector is equal to or less than half of the first servo interruption period.

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Kawasaki, Japan

Yukio Abe