Abstract: A system comprising a plurality of storage systems, which uses storage devices of multiple levels of reliability. The reliability as a whole system is increased by keeping the error code for the relatively low reliability storage disks in the relatively high reliability storage system. The error code is calculated using hash functions and the value is used to compare with the hash value of the data read from the relatively low reliability storage disks.

Abstract: System and method for automated page-based management in storage systems. The system includes host computers, file servers and a storage system having automated page-based management means. The storage system interface receives instructions to change the condition for decision for migration regarding particular parts or the whole volume. The host computer can control execution of the migration performed by the storage system by specifying areas or volumes with the condition via the interface. Highly optimized, appropriate data placement and data relocation in computer system can be achieved when the application, host computer or management computer can recognize or predict the usage of the data or files. The storage system having automated page-based management may include compression/decompression and a control method for the compression and decompression process.

Abstract: A system comprising a plurality of storage systems, which uses storage devices of multiple levels of reliability. The reliability as a whole system is increased by keeping the error code for the relatively low reliability storage disks in the relatively high reliability storage system. The error code is calculated using hash functions and the value is used to compare with the hash value of the data read from the relatively low reliability storage disks.

Abstract: System and method for automated page-based management in storage systems. The system includes host computers, file servers and a storage system having automated page-based management means. The storage system interface receives instructions to change the condition for decision for migration regarding particular parts or the whole volume. The host computer can control execution of the migration performed by the storage system by specifying areas or volumes with the condition via the interface. Highly optimized, appropriate data placement and data relocation in computer system can be achieved when the application, host computer or management computer can recognize or predict the usage of the data or files. The storage system having automated page-based management may include compression/decompression and a control method for the compression and decompression process.

Abstract: A remote copy system includes a first storage device performing data transmission/reception with a host computer, a second storage device receiving data from the first storage device, and a third storage device receiving data from the second storage device. The first storage device includes a logical volume, the second storage device includes a logical volume being a virtual volume, and the third storage device includes a logical volume. The first storage system changes the state of a first pair of the logical volumes based on the state of a second pair of the logical volumes. With such a remote copy system and a method for use therein, any data backup failure can be prevented.

Abstract: A semiconductor storage employs a base substrate (101) having a command/address external terminal group (CA), a data input/output external terminal group (DQ), and a single chip select external terminal (CS), and also comprises a plurality of memory chips (110) to (113) mounted on a base substrate (101), each of which can individually carry out read and write operations. The terminals (CA), (DQ), and (CS) are connected to an interface chip (120). The interface chip (120) has a chip select signal generation circuit that can individually activate a plurality of memory chips (110) to (113) on the basis of an address signal fed by way of the terminal (CA) and on the basis of a chip select signal fed by way of the terminal (CS).