Hitachi, Ltd.

Hitachi Computer Peripherals Co., Ltd.

Microcomputer Engineering Ltd.

Akira Kurano

Akira Yamamoto

Masafumi Nozawa

Hisashi Takamatsu

Toshihiko Tamiya

Hiroyuki Kitajima

Hisaharu Takeuchi

Yoshiro Shiroyanagi

Katsunori Nakamura

Hirofumi Inomata

Kiyoshi Hisano

Toshio Nakano

Yoshihiro Asaka

Shigeo Homma

Eiju Katsuragi

Naoya Takahashi

Mikito Ogata

Yoshiaki Kuwahara

Mamoru Tohchi

Masahiro Nakayama

Hidetoshi Sakaki

Ikuo Kawaguchi

Toru Nishigaki

Akihito Ogino

Akihiko Togawa

Toshiaki Hatanaka

Yukihisa Kashima

Takehiro Ishikawa

Hiroshi Nishijima

Shigeo Honma

Shigeru Kishiro

Katsuhiro Tsuneta

Kiyotaka Takahashi

Tsuneo Hirose

Michio Miyazaki

Kosaku Kambayashi

Masayuki Hoshino

Toshiaki Tsuboi

Toshiyuki Haruna

Kenji Nishimura

Takikazu Takeuchi

Yuji Yoshida

Yoshiro Shiroyana

Kimiko Shigihara

Riichi Nakano

Kazuto Takahashi

Tadayuki Ichiba

In an information processing system having a data processing apparatus, a control unit for a cache memory, and a storage unit for storing a record, respectively interconnected together, wherein when the control unit receives from the data processing apparatus a write request for a record to be written and if the record to be written is not being stored in the cache memory, the control unit receives a data to be written in the object record from the data processing apparatus and stores the received data in the cache memory. After notifying the data processing apparatus of a completion of a data write process, the control unit checks if the object record in which the data stored in the cache memory is being stored in the storage unit, if the object record is being stored in the storage unit, the data in the cache memory is written in the storage unit, and if not, the data in the cache memory is not written and such effect is notified to the data processing apparatus.

Cache control method and apparatus

A disk array device selects a redundant generation method for reducing the overhead and improving the reliability associated with generating redundant data. The disk array device includes a disk controller connected to and controlling an array of disk drives. The disk controller includes a redundant data generator, a difference data generator, and a redundant data generation method selector. The redundant data generator is able to generate redundant data via a read and modify method and an all stripes method. The disk array device selects a method of generating redundant data from a method of read and modify and all stripes, and a method of generation in a drive and a method of difference, both of which are executed to generate redundant data on a disk drive.

Disk array device with selectable method for generating redundant data

A disk array device selects a redundant generation method for reducing the overhead and improving the reliability associated with generating redundant data. The disk array device includes a disk controller connected to and controlling an array of disk drives. The disk controller includes a redundant data generator, a difference data generator, and a redundant data generation method selector. The redundant data generator is able to generate redundant data via a read and modify method and an all stripes method. The disk array device selects a method of generating redundant data from a method of read and modify and all stripes, and a method of generation in a drive and a method of difference, both of which are executed to generate redundant data on a disk drive. The disk array device selects the method of generating redundant data that will minimize the time required to process, transfer and store both the received host data and the generated redundant data based on the length of write data received from the host, an access pattern specified by the host, by the current load state of the disk drives, and by the existence of a failure state in a disk drive. Divided write data and previous data to be updated may be transferred depending on the write data length.

A disk array stores data records and parity records. The data records are transferred to the disk array through a control unit that is connected to a host processor. The disk array is part of a disk unit having a processor for generating parity records from information sent by the control unit to the disk unit. The parity record is generated and stored in the disk unit to reduce the number of data transfer operations between the control unit and the disk unit for storage systems using disk array disk units.

Parity storage unit, in a disk array system, for generating updated parity data from received data records

A method, apparatus and computer program for controlling data migration in an information processing system which includes a central processing unit (CPU), a new storage system connected to the CPU and an old storage system connected to the new storage system. In the information processing system data migration is conducted to transfer data from the old storage system to the new storage system. The invention operates by permitting access by the CPU to the storage systems during data migration. When an access by the CPU is generated the invention determines whether the access is to a region where data migration has been completed or to a region where data migration has not been completed. If the access is to a region where data migration has been completed, then processing of the access is handled by the new storage system. If the access is to a region where data migration has not been completed, then processing of the access is handled by the old storage system causing data related to the access to be transferred from the old storage system to the new storage system. The speed of data migration can be adjusted based upon the utilization of the resources of the information processing system and information of the priority of access to the new storage system by the CPU.

Method of data migration

A disk array device selects a redundant data generation method for reducing the overhead and improving the reliability associated with generating redundant data. The disk array device includes a disk controller connected to and controlling an array of disk drives. The disk controller includes a redundant data generator, a difference data generator, and a redundant data generation method selector. The redundant data generator is able to generate redundant data via a read and modify method and an all stripes method. The disk array device selects a method of generating redundant data from a method of read and modify and all stripes, and a method of generation in a drive and a method of difference, both of which are executed to generate redundant data on a disk drive. The disk array device selects the method of generating redundant data that will minimize the time required to process, transfer and store both the received host data and the generated redundant data based on the length of write data received from the host, an access pattern specified by the host, by the current load state of the disk drives, and by the existence of a failure state in a disk drives. Divided write data and previous data to be updated may be transferred depending on the write data length.

Parity storage unit, in a disk array system, for generating updated

Parity storage unit, in a disk array system for generating updated

Storage unit with parity generation function and storage systems using

Cache control by adding record identification information to partial

A buffer memory capable of storing contents of a plurality of tracks of a disk volume is provided in a disk controller or a disk drive, and in dump processing requested by a higher rank unit (CPU) to the disk controller, the data is immediately transferred from the buffer memory if the data to be dumped is present in the buffer memory, and if the data to be dumped is not present in the buffer memory, dump prefetching into the buffer memory is started and the execution of the dump processing is interrupted so that an on-line input/output operation other than the dump processing is accepted. When the dump prefetching into the buffer memory is over, the interrupted dump processing is resumed.

On-line dumping system and disk sub-system

Growing community of inventors

Odawara, Japan

Akira Kurano