Hitachi, Ltd.

Soichi Isono

Yasuo Inoue

Hidefumi Masuzaki

Hidehiko Iwasaki

Naoya Takahashi

Hiroyuki Kurosawa

Masayuki Hoshino

Tatuya Ninomiya

Akira Kojima

Jun Matsumoto

Takashi Oeda

Toshimitsu Kaku

Motoyasu Tsunoda

Kiyoshi Honda

Yasushi Fukuda

Hitoshi Komatsu

Yuzuru Maya

Syoichi Miyazawa

Fukashi Ohi

Noriyuki Karasawa

Yuji Yamane

Akihito Ogino

Akira Ohtsuji

Minoru Yoshida

Kunio Watanabe

Hiroshi Ide

Toshio Niihara

Satoshi Kawamura

Kiyoshi Matsumoto

Shigenori Okamine

Masatoshi Ichikawa

Yukari Nagashige

Nobuhiro Matsumura

Kouzi Shida

Naoto Matsumani

Kunihiko Kizaki

A storage system, coupled to a host computer, including at least one controller receiving data from the host computer, and a plurality of memory units connected to the controller. The controller generates parity data and sends the data and the parity data to the memory units. The memory units include a semiconductor memory device which stores the data and the parity data permanently.

Storage system having a semiconductor memory device which stores data and parity data permanently

A storage system to be connected to a large-scale computer includes a plurality of host adaptors connected to a host device, a plurality of storage device for storing data from the host device, a plurality of disk adaptors connected to the storage devices, a plurality of caches for temporarily storing data transferred between the host adaptors and the disk adaptors, and two buses connected to the host disk adaptors, and the caches. The buses transfer data among the host and disk adaptors and the caches.

Storage system having data format conversion function

Storage system

A storage system to be connected to a large-scale computer includes a plurality of first logical units connected to a host device, a plurality of second logical units connected to a storage device, a plurality of cache memories, and a common bus wired between these logical units and memories. The plurality of first logical units, the plurality of second logical units, and the plurality of cache memories are all made in the form of modules. The modules are detachably mounted to the common bus disposed on a back plane. The storage device can be made up of a plurality of small-size storage units arranged in an array. Thus, the storage system realizes its scalability. Since the plurality of first logical units, the plurality of second logical units, and the plurality of cache memories are duplexed and the common bus is made in the form of 2 channels, the storage system can perform degrade operation. Since plurality of first logical units, the plurality of second logical units, and the plurality of cache memories allow hot replace, the storage system can realize its non-stop maintenance.

Storage system having plural buses

Multibeam optical disk record and reproduction apparatus and method, in which at least two light beams generated are concentrated in different positions of on recording tracks of a recording medium to record or reproduce data to or from the recording medium on the different positions at the same time. The light beams are moved independently of each other across the recording tracks so that any one light beam is movable during the recording or reproducing of data by another light beam. This allows parallel recording/reproducing with a plurality of light beams without producing areas unaccessed due to the jumps of the light beams.

Multibeam optical disk record and reproduction apparatus and method

A recording apparatus includes a plurality of ECC units operating selectively and independently. A medium access unit reads data from a recording medium in a read mode, and writes data from a host device to the recording medium in a write mode. The data read out from the recording medium contains a reproduction data and a medium reproduction check symbol added to the reproduction data, and data written contains a recording data and a medium recording check symbol added to the recording data. The reproduction data or the recording data is stored in a buffer. In a read mode, the reproduction data from the medium access unit is transferred to the host device through the buffer and in the write mode, the recording data from the host device is transferred to the medium access unit through the buffer. Each ECC units detects any error of the data stored based on the check symbol added to the data stored in the buffer during the transfer operation, corrects the data stored when the error is detected, and generates a check symbol from the data transferred. The check symbol generated is transferred to a destination of transfer after the data to be transferred.

Recording apparatus

Independent error detection method/apparatus for a disk controller, and

A parallel computer system and a block transfer method and computer program for use with the parallel computer system which includes at least one processing unit divided into a plurality of logical processing units and a connecting device which exchanges commands and acknowledgements with the processing unit. The connecting device edits into a single command or acknowledgement individual commands or acknowledgements to be sent to the logical processing units and sends the single command or acknowledgement to the processing unit. The single command or acknowledgement includes a header, a command or acknowledgement code, logical processing unit numbers and pieces of command or acknowledge information corresponding to the logical processing units. The processing unit divides the single command or acknowledge into the individual commands or acknowledgements for the logical processing units and notifies the latter of these commands or acknowledgements. The invention operates in a similar manner when sending commands or acknowledgements from the logical processing units to the connecting device.

Block transfer method for use with parallel computer system

A disk drive has two channels of upper interfaces, and one channel is connected to a disk array controller, and the other channel is connected between a plurality of disk drives. A data disk drive reads the old data on the recording medium, calculates the exclusive OR of the old data and the corresponding data from the disk array controller, and transfers it to a parity disk as pseudo-parity data from the other channel. The parity disk drive reads the old parity data on the recording medium, calculates the exclusive OR of the old parity data and the pseudo-parity data, and writes it as new parity data.

Disk array subsystem and data generation method therefor

A command is issued from a processing unit to an on-line storage unit and transferred from the on-line storage unit to a back-up storage unit. The received commands are processed in the respective storage units. An overhead of the on-line storage unit is reduced in a hot stand-by system. Storage contents of the on-line storage unit and the back-up storage unit are made coincident in a structure having a plurality of processing units, where the on-line storage unit and the back-up storage unit are connected through a channel device.

Method for ensuring data coherency for redundat storage by transferring

Storage system realizing scalability and fault tolerance

When file and command management means in a secondary storage system is instructed to store a new file by a command containing file identification information from a host computer, the means transfers it to new file address determination means, which then references a disk management table to find a free area and considers characteristics of the file, the configuration of the secondary storage system, etc., to determine an optimum area as an area for registering the new file. Also, the address of the determined area is related to file identification information of the file and a correspondence therebetween is registered in a local file management table. The file and command management means stores the file in the determined area in a disk unit via a disk unit controller. Then, file placement optimization can be carried out independently of the type of secondary storage system.

Computer system including a computer which requests an access to a

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Chigasaki, Japan

Soichi Isono