Fujitsu Corporation

Kabushiki Kaisha Toshiba

Fujitsu Limtied

Toru Yokohata

Takayuki Yamamoto

Yoshiharu Kasamatsu

Takashi Toyoguchi

Takahiro Imamura

Yoshifumi Mizoshita

Atsuo Iida

Seiji Yoneoka

Yasuo Noguchi

Kazutaka Ogihara

Riichiro Take

Masaki Kameyama

Ryosuke Koishi

Masaharu Sugimoto

Kenrou Yamamoto

Hiroshi Ishikawa

Susumu Yoshida

Kazuhiro Watanabe

Masahisa Tamura

Takayuki Kawabe

Hitoshi Komoriya

Tohru Fujimaki

Yoshiaki Ikai

Satoru Momose

Mitsuhiko Ohta

Arata Ejiri

Hiroyuki Hyodo

Satoshi Ikuta

Masahiro Ozeki

Toshiya Fujita

Yojiro Ochiai

Naoki Satake

A cooling apparatus includes: a pump transports a refrigerant; and a controller controls a discharge amount of the pump depending on a calorific value of a heat generating body. And a cooling method includes: measuring a calorific value of a heat generating body; and controlling a discharge amount of a pump, which transports a refrigerant used for cooling the heat generating body, depending on the calorific value.

Cooling apparatus, cooling method, and data processing system

A storage system is disclosed that stores data across plural storage devices. The storage system includes plural modules. Each of the modules includes a storage device including a data storage section that has plural slice areas to store data elements one in each, and a control-information storage section that stores control information of the plural slice areas, a communications-function section having a function of sending and receiving the data elements stored in the slice areas in the data storage section. The modules communicate with each other to replicate the data element stored in the slice area into an unused slice area in another module so as to have data redundancy.

Storage system including a plurality of modules having different control information

A recording method for a disk device includes the following steps. Sequential data is written into the medium along the track in a predetermined radial direction. Information indicating an end position along the track where the end of the sequential data is written into is stored. The information is read when additional sequential data is to be written into the medium. The additional data is written from a position along the track next to the end position indicated by the information in the predetermined radial direction. The information is updated so as to indicate an end position along the track where the end of the additional sequential data is written into.

Recording method for a disk device having recording regions different in recording density

The present invention relates to a system capable of carrying out efficient and stable system operation control even if a usage rate of the entire system varies under a situation in which the characteristics of storage units, such as maximum available total capacity and speed performance, are largely different from each other. Therefore, the system according to the present invention is composed of a monitor unit for monitoring information on a total volume of data stored in each of the storage units or in all the storage units, an index value calculating unit for calculating an index value on the basis of the monitor result and a location unit for distributively locating or relocating logical storage areas in physical storage areas on a plurality of storage units on the basis of the calculated index value.

Migrating data in a distributed storage system based on storage capacity utilization

Provided is a new apparatus for measuring a flying height of a head requiring none of a specific magnetization pattern, that is, ahead flying height measurement apparatus for use within a disk drive including a reading head, including: a signal replay unitfor replaying a signal from the reading head; filter unitsand, being connected to the signal replay unit, for filtering the replayed signal; amplitude detection unitsand, being connected to each of the filter units, for detecting a maximum amplitude or a representative value close thereto from the filtered replayed signal; and a calculation unitfor calculating a flying height of the reading head within the disk drive by using the maximum amplitude, or the representative value close thereto, which is detected by the amplitude detection unit.

Flying height measurement apparatus and method therefor

Firstly, in order to check the noise level of a device, DC erasure is applied to a magnetic recording medium and the magnetic recording medium is read. Then, a test signal including a first order component and a third order harmonic frequency is written into the magnetic recording medium. The written test signal is read and Fourier transform is applied to the read signal to obtain the respective amplitude of the first order and third order harmonic components. Then, it is determined whether the amplitude of the third order harmonic component is sufficiently large compared with the obtained noise level. If the amplitude is sufficiently large, the flying height of the head is estimated using both the first order and third order harmonic components. If the amplitude is not sufficiently large, the flying height of the head is estimated using only the first order component.

Head flying height measuring apparatus in magnetic storage device

A method of detecting a gap between a head and a recording medium in an information-recording/reproducing apparatus that uses the head to record and reproduce information in and from the recording medium. In the method, the gap between the head and the recording medium is alternately increased and decreased, thereby gradually reducing the gap between the head and the recording medium. A detection signal is detected from which to determine a contact between the head or a slider supporting the head and the recording medium. When it is determined that the head or the slider has contacted the recording medium, the head is stopped and moved away from the recording medium to a prescribed position, and data representing a distance the head has moved to contact the recoding medium is acquired.

Information-recording/reproducing apparatus and method of detecting the gap between a head and a recording medium

A magnetic recording medium inspection method detects small protrusions that constitute defects on the surface of a magnetic recording medium. The method includes flying a glide inspection head at a predetermined height over the surface of the moving magnetic recording medium; detecting a contact duration time during which the glide head is in contact with a protrusion on the surface of the magnetic recording medium using a contact detection sensor attached to the glide inspection head; and determining the small protrusion based on the contact duration time.

Method of inspecting magnetic recording medium based on contact duration time

A magnetic disk evaluation apparatus includes an evaluation head for evaluating a magnetic disk, and a support member for supporting the evaluation head. The support member supports the evaluation head in a state where a flying surface of the evaluation head and a surface of a magnetic disk make a flying pitch angle of 95 &#x3bc;rad or more.

Magnetic disk evaluation apparatus

An acoustic emission sensor is mounted on a flying slider opposed to a rotating recording medium, for example. The acoustic emission sensor outputs a detection signal in response to the sound of collision. When a protrusion exists on the recording medium, the flying slider is expected to collide against the protrusion at a predetermined fixed angular position. A variation is induced in the detection signal based on the collision between the flying slider and the protrusion in synchronization with the rotation of the recording medium. Specifically, when a variation is synchronized with the angular position signal of the recording medium, the variation should correspond to a protrusion existing on the surface of the recording medium. If the component corresponding to the variation is extracted out of the detection signal, a protrusion on the recording medium can be determined at a higher accuracy.

Method of detecting protrusion on recording medium and detecting apparatus therefor

A protector protuberance is formed on a head slider incorporated in a recording medium drive such as a hard disk drive. The protector protuberance is allowed to collide against a contamination on a recording medium in front of a head element mounted on the head slider. The head element can be protected from collision against the contamination behind the protector protuberance. The protector protuberance is located as close to the head element as possible. Even with a smaller protector protuberance, the front and rear support protrusions contact the recording medium so as to hold the slider body above the surface of the recording medium. An increase can be prevented in the adsorption acting between the slider body and a lubricant agent spreading over the surface of the recording medium. A smaller protector protuberance enables the head element to approach the recording medium as close as possible upon read/write operations.

Head slider having protector protuberance in front of head element

A protection film is layered over the trailing or outflow end surface of a slider body in a head slider for a recording medium drive. A head element is embedded within the protection film. The head element generates heat in response to the supply of an electric current. The heat causes thermal expansion of the protection film. The tip end of the head element thus excessively approaches the recording disk beyond the medium-opposed surface of the head slider. The flying height of a protection protuberance is set smaller than a flying height of the head element even when the protection film suffers from thermal expansion. The protection protuberance is allowed to trace an orbit closer to the recording medium than the orbit of the head element. The protection protuberance is allowed to collide against obstacles on the recording medium in front of the head element.

Recording medium drive including head slider having protection protuberance standing on air bearing surface

A magnetic disk drive includes a magnetic recording medium rotatably mounted in a housing, a magnetic head slider having an electromagnetic transducer for reading/writing data from/to the magnetic recording medium, and an actuator for moving the magnetic head slider across tracks of the magnetic recording medium. The magnetic head slider has a medium opposing surface opposed to the magnetic recording medium, and is formed with an air bearing surface and a plurality of projections. The magnetic recording medium has a nondirectional texture which includes a surface roughness composed of numerous microscopic projections having an average top radius of 0.3 &mgr;m to 0.75 &mgr;m.

Magnetic disk drive capable of preventing stiction of magnetic head

A magnetic disk drive includes a magnetic recording medium rotatably mounted in a housing, a magnetic head slider having an electromagnetic transducer for reading/writing data from/to the magnetic recording medium, and an actuator for moving the magnetic head slider across tracks of the magnetic recording medium. The magnetic head slider has a medium opposing surface opposed to the magnetic recording medium, and is formed with an air bearing surface and a plurality of projections. The magnetic recording medium has a unidirectional texture which includes a surface roughness composed of numerous microscopic projections having an average top radius of 1 &mgr;m or more.

A head slider is composed of a substrate having a transducer on its outflow end, a rail plane formed on a surface near both sides of the substrate facing a magnetic disk. The head slider further includes a plurality of projection elements formed on the rail plane. When the slider is floating over the magnetic disk, the distance between the projection elements and the magnetic disk is greater than the distance between the outflow end of the slider and the magnetic disk.

Growing community of inventors

Kawasaki, Japan

Toru Yokohata