Hitachi, Ltd.

Kazuo Nakagoshi

Naoya Takahashi

Yoshihiro Moribe

Akira Chuma

Makoto Kogai

Takuji Ogawa

Jun Naruse

Kazuhisa Shiraishi

Minoru Yoshida

Hiroshi Fukui

Kenichi Takamoto

Yutaka Sugita

Moriaki Fuyama

Masaaki Hayashi

Hiroshi Nishida

Shinji Narishige

Tsuyoshi Takahashi

Kanji Kawakami

Hisao Honma

Yokuo Saitoh

Masanori Tanabe

Mikio Takahashi

Takeo Hayakawa

Ken-ichi Takamoto

Nobukuni Ohkubo

Hiroshi Ikeda

Yoshihiro Shiroishi

Masahiko Sato

Masafumi Nozawa

Toshiyuki Utsuki

Hajime Aoi

Naoki Kodama

Takashi Kawabe

Makoto Morijiri

Hideaki Amano

Fumio Kugiya

Kazuo Sakai

Masao Iwakura

Katsuya Mitsuoka

Tomio Suzuki

Nobuyuki Okunaga

Makoto Aihara

Shunichiro Kuwatsuka

Toshiyuki Haruna

Asao Sasamoto

Katsumoto Onoyama

Tatsuo Murai

Tatsuya Ishigaki

Yoshiyuki Hirano

Yoshio Yukawa

Yoshikazu Tsuji

Hideo Maekawa

Kenjiro Kai

Yasuo Yamamoto

Eizi Ashida

Motohiro Nakai

Toshiaki Kojima

Shoji Ozaki

Chuma Akira

Kunihiro Motoyoshi

Masashi Sakuma

Noriaki Miniamide

Syoji Umemoto

Naoyuki Fukada

A magnetic disk drive has a housing for a 3.5 inch form factor and disk media of a diameter for a 2.5 inch form factor. The smaller disk media rotate at a high speed while consuming low electric lower and generating less heat while providing for quick access speeds. Usually, when the magnetic disk media are rotated at a higher speed, the electric power consumption and heat generation are increased because of the load increase. This problem is avoided with the use of cooling fins placed about the periphery of the disk media. Further, the smaller size disk media enable a decrease in torque loss during on-load rotation with the media, and a decrease of electric current to the spindle motor during rotation.

Disc drive having 3.5 inch form factor housing and 2.5 inch form factor disk media

A magnetic disc apparatus has a large recording density of 120 megabits per square inch or more, and defines a relationship among a pole thickness (Pt) of thin-film magnetic heads disposed in the magnetic disc apparatus, and a saturation flux density (Bs) of cores of the heads and a recording wavelength (.lambda.) for the thin film magnetic discs have a coercivity of 1800 Oe or more, wherein a levitation space between the head and the disc is 0.15 .mu.m or less.

Large capacity magnetic disc apparatus with a particular relationship

The write data is entered from the upper unit into a nonvolatile cache provided in a controller inside of each disk unit through a channel adaptor, a cache shared by each disk, and a disk adaptor. The data from the cache is compressed by the data compressing and restoring device and is written in the disk. At a time, the management information for compressed data is written in the cache and the disk as well. In case of breaking the management information of the cache when a failure takes place in the cache memory, the management information is written for each disk. Hence, the breakage does not have an adverse effect on the other disks. If the management information of the cache is broken, the management information given into the disk may be replaced with the broken information.

Data storing system and data transfer method

A semiconductor storage device transfers data with an information processing device and includes a non-volatile semiconductor memory in which data is electrically re-writable, a volatile semiconductor memory connected to the non-volatile memory and temporarily storing data of the non-volatile semiconductor memory, and a CPU connected to the volatile semiconductor memory and the non-volatile semiconductor memory. The CPU controls the transfer of data among the non-volatile memory, the volatile memory and the CPU. The CPU also transfers data with the information processing device in accordance with a fixed-length form for data. When an access from the CPU to the volatile semiconductor makes a miss hit (i.e., misses), the CPU accesses the non-volatile semiconductor memory. When a failure is generated in the non-volatile semiconductor memory or when a predicted service life of the non-volatile semiconductor memory is elapsed, the non-volatile semiconductor memory can be substituted by an alternate memory.

Semiconductor disk storage

An external storage system is connected to a host system. A controller unit interposed between disk drives and the host system has a large capacity buffer memory with a battery providing non-volatile storage, a plurality of host interfaces and a plurality of drive interfaces. All the accesses made to the disk drives from the host system are realized via the buffer memory which allows a high-speed access. Read/write processing performed for the buffer memory by the host system is executed asynchronously with read/write processing performed between the buffer memory and the disk drives. The drive interface and the host interface area released during a period in which operation of the disk drive is waited for and recoupled upon data transfer.

System for controlling data flow between plurality of host interfaces

A semiconductor storage device is connected to at least one magnetic storage device. The input and output of data is made between the semiconductor storage device and an information processing device. The semiconductor storage device includes an electrically erasable non-volatile semiconductor memory which stores directory information of data stored in the magnetic storage device, a volatile semiconductor memory which has a storage capacity smaller than that of the non-volatile semiconductor memory and the storage contents of which are updated to store a part of the directory information having a higher frequency of access from the information processing device, and a CPU connected to the volatile semiconductor memory and the non-volatile semiconductor memory for making access to the volatile semiconductor memory and the non-volatile semiconductor memory in accordance with an access request from the information processing device, wherein when access to the volatile semiconductor memory made for access from the information processing device to the magnetic storage device hits on the part of the directory information, the CPU transfers the part of the directory information to the information processing device without making access to the non-volatile semiconductor memory and the information processing device makes access to the magnetic storage device on the basis of the part of the directory information When a failure is generated in the non-volatile semiconductor memory or when a predicted service life of the non-volatile semiconductor memory is elapsed, the non-volatile semiconductor memory is substituted by an alternate memory.

Semiconductor disc storage

A magnetic disk apparatus includes a base coupled to a supporting frame by means of a damping member so that the vibration caused by the operation of the internal actuator subsides. The damping member may include an adhesive resilient material disposed between the base and the supporting frame.

Vibration absorbing structure for a magnetic disk apparatus

Data storing system and data transfer method with a plurality of disk

A magnetic head for reading from and/or writing to a magnetic information storage medium has a substrate on which a plurality of thin films are formed in sequence. The films provide a magnetic circuit having a magnetic gap, a bottom pole piece and a top pole piece overlying said bottom pole piece. The top pole piece is formed as a tip portion adjoining the magnetic gap and a rear portion which makes magnetic contact with the tip portion. The rear portion is formed in the sequence after the tip portion. To ensure accurate thickness and width of the tip portion, a non-magnetic protective film is formed on the tip portion after the tip portion is formed and before the rear portion is formed.

Magnetic information storage apparatus including magnetic head and

A housing for an information recording and reproducing apparatus is adapted for increased storage capacity and an increased operating speed by placing a relatively larger number of relatively smaller magnetic disks each having a relatively smaller mass and a relatively smaller recording and reproducing surface in an enclosure and housing the enclosure for a relatively larger magnetic disc in a box-like frame. A shock absorbing device is disposed between the enclosure and the box-like frame to absorb shock. A circuit assembly for controlling the operation of recording and reproducing is disposed outside the enclosure and between the frame and the enclosure.

Mounting structure for information recording and reproducing apparatus

Magnetic disc storage unit for electronic computer

A magnetic head disk apparatus has a housing with one thicknesswise end providing the front side and the other thicknesswise end providing the rear side of the apparatus. The apparatus further has a plurality of head disk assemblies each including at least one combination of a magnetic head and a magnetic disk. The head disk assemblies are arranged in a plurality of rows not only in heightwise and breadthwise directions but also in the thicknesswise direction of the housing. With this arrangement, it is possible to accommodate a multiplicity of head disk assemblies with a high space factor in the housing.

Magnetic disk apparatus having improved arrangement of head disk

An electronic apparatus, such as a disk apparatus, has a plurality of electronic units such as magnetic head-disk units and at least one power source unit for supplying power to the electronic units. The arrangement of the electronic apparatus is such that, on a frame of the apparatus, the plurality of electronic units are vertically arranged in such a manner as to form a first arrangement system, while the at least one power source unit is arranged in such a manner as to form a second arrangement system above the first arrangement system. The apparatus has an air flow passage for causing cooling air to flow from a lower portion of the electronic apparatus to the inside thereof, pass through the first arrangement system, thereby pass through the second arrangement system, and then be discharged to the outside of the apparatus. This arrangement enables cooling air to flow in a simplified manner, which in turn enhances the cooling efficiency, and also enables electrically connecting cables to be arranged in a simple wiring system.

Disk apparatus having an improved cooling structure

Because of increase in data recording density on a magnetic disk in recent years, a minute defect which posed no problem in the past exerts adverse influence upon the recording and reproducing characteristics. An object of the present invention is to provide a method and an apparatus for detecting minute defects on a magnetic disk. In order to achieve this object, the present invention was made on the basis of the recognition that a large defect on the magnetic disk largely decreases the amplitude of the reproduced signal and shifts its phase, whereas a small defect does not decrease the amplitude of the reproduced signal so largely but causes a phase shift. Therefore, defects on the magnetic disk are detected by monitoring the amplitude decrease and phase shift of the reproduced signal.

Method and apparatus for detecting minute defects on magnetic disk by

A method of first erasing the full width of a recording track using an erase core before recording data into a flexible disk and then writing the new data into the erased area using a read/write core, and an apparatus for effecting the same are disclosed. The erasure by the erase core is done in an AC manner. A gap pattern used to form a gap area is written by the read/write core into a portion of the erased area where no valid data has been written.

Apparatus for and method of writing/reading data into/from a flexible

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Odawara, Japan

Kazuo Nakagoshi