Hitachi, Ltd.

Toru Nishigaki

Akira Yamamoto

Akira Kurano

Kiyoshi Hisano

Yoshitaka Watanabe

Koji Sasaki

Koichi Haruna

Takashi Doi

Yoshiro Shiroyanagi

Toshinori Watanabe

Sadasaburo Kanai

Miho Nonomura

Hiroshi Motoyama

Teruo Yakata

Kazuaki Masamoto

Yoshiro Shiroyana

There are provided a backup version page table in a storage for providing a correspondence between the pages of a database and the slots in a database storage medium in which the contents of pages to be recovered, if necessary, are stored; a current version page table for providing a correspondence between pages updated by a transaction and slots in the database storage medium wherein the updated contents of the pages are stored; and a journal file for recording various system journals; wherein the updated page contents are stored in the database stored medium at the slots not-used at that time and found with reference to the backup version page table and the current version page table. According to an aspect of another embodiment, there are provided a database constructed of a plurality of sub-areas; a differential file for each sub-area, and a backup file for each sub-area for copying the contents of each sub-area; wherein if the information in a certain sub-area of said database is updated, the updated information is stored in the differential file for the sub-area, and information is recovered using the backup file and the differential file for the certain sub-area.

Method and apparatus for database update/recovery

An autonomous resource management method for improving performance of a system in which plurality of process units compete for resources. Previously determined allocation policies are stored in memory along with system status data, control data and an evalution of the effectiveness of the allocation policy. During the operation of the system, the status is detected and an allocation policy is retrieved from memory based on the detected status. The allocation policy is then modified and sent to the scheduler. The effect of modifying the allocation policy is detected and an evaluation of the modified allocation policy is stored in memory. Inferior allocation policies are deleted from memory.

Autonomous resource management system with recorded evaluations of

A computer system having a disk cache unit between a disk unit and the main storage unit. Ordinarily, the data transfer processing is carried out between the disk unit and the disk cache unit and between the disk cache unit and the main storage unit in this case. The present invention is characterized by enabling these two data transfer operations to be executed in parallel and to prevent a director from becoming the bottleneck of the processing due to the concentrated processing requests. For this purpose, the present invention provides for conducting a data transfer between the disk cache unit and a disk unit while a data transfer is taking place between the main storage unit and the disk cache unit. The director is configured, for example, with two data transfer controlling systems and two data transfer units for carrying out data transfer according to instructions for the two data transfer controlling systems.

Parallel transfer type director means

The present invention relates to a computer system having a disk cache unit between a disk unit and the main storage unit. Ordinarily, the data transfer processing is carried out between the disk unit and the disk cache unit and between the disk cache unit and the main storage unit in this case under control of a director. The present invention is characterized by enabling these two data transfer operations to be executed in parallel and to prevent the director from becoming the bottleneck of the processing due to the concentrated processing requests. For this purpose, the present invention provides for a data transfer between the disk cache unit and a disk unit while a data transfer is taking place between the main storage unit and the disk cache unit.

Method and system for concurrent data transfer disk cache system

An input/output control system has a control unit including a first controller connected between a channel and a data buffer for controlling the transfer of data therebetween and a second controller connected between the data buffer and a plurality of input/output devices for controlling the transfer of data therebetween. A start action of the input/output device is effected in an off-line mode from the control unit. The amount of data stored in the data buffer is checked each time the transfer of data occurs between the channel and the data buffer. In the case of a read processing, when the amount of data stored in the data buffer becomes less than a first predetermined value, data is transferred for preload from the input/output devices to the data buffer. In the case of a write processing, when the amount of data stored in the data buffer exceeds a second predetermined value, data is transferred for after-write from the data buffer to the input/output devices. Each of the first and second predetermined values is determined depending on the amount of input/output devices which are in an active state at that time. When each of the active input/output devices is allocated with m (.gtoreq.2) unit fields of the data buffer each of which has a capacity of K/(mn) where K is the whole capacity of the data buffer and n is the number of the active input/output devices, the first and second predetermined values may be K/(mn) respectively.

Data transfer control system for controlling data transfer between a

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Sagamihara, Japan

Toru Nishigaki