Hitachi, Ltd.

Mamoru Tohchi

Hisaharu Takeuchi

Akira Kurano

Hisashi Takamatsu

Ikuo Kawaguchi

Masahiro Nakayama

Yukihisa Kashima

Takao Sato

Yoshihiro Uchiyama

Yoshiko Matsumoto

Hisayoshi Kawabata

Satoshi Numakura

A storage system comprises a disc drive unit including a plurality of logical drive groups each having a plurality of physical drives, and a disc drive control unit for controlling the information transfer between the disc drive unit and the host system. The logical data arriving from the host system is divided into a plurality of continuous data blocks, from which redundant data is prepared for data restoration. The redundant data is added to the continuous data blocks to provide updated logical data. The storage system is controlled in such a way as to write the updated logical data into a plurality of physical drives. In the case where a fault develops in any of the data blocks of the physical drives to be accessed, redundant data is generated from the updated logical data. The data block of the updated logical data of the physical drive corresponding to the data blocks that has not developed a fault, among the data blocks and the redundant data making up the updated logical data, is stored in the physical drive. The data block of the updated logical data of the physical drive corresponding to the data block that has developed a fault is stored in the nonvolatile memory. The completion of writing the updated logical data into the storage system is reported to the host system. In re-updating the updated logical data, the data block of the re-updated logical data corresponding to the data block of the physical drive that has developed a fault is stored in the physical drives. The data block stored in the nonvolatile memory are stored into an alternate block allocated to the physical drives.

Storage system and method of control

An external memory device subsystem and a data recording device, which issue a command specifying previously a plurality of tracks in a rotary type memory device prior to a read or write instruction issued from the data processing unit of higher rank to the rotary type memory device through a control unit; select continuously the plurality of tracks previously specified, at executing a read or write command after the execution of the command; and in this way can read/write continuously without wait time for rotation a plurality of tracks distant from each other within the same cylinder.

Method of changing the track and recording data

A magnetic disc storage system, in which operation for erasing information otherwise left to remain in succession to data records on a rotatable storage medium during a remaining period of one rotation of the medium is omitted. In response to a command commanding access to the stored data, a table containing the lengths of the stored data is referred to. When it is detected that a record having a storage location commanded to be accessed exceeds the associated stored length of the recorded data, a command error is messaged to a controller of the rotatable storage medium in place of executing the access.

Disk control method of format write operation using data distance on a

A method of emulating an original record format for a new rotating storage device, including the steps of;

Rotating storage track format emulation

An external memory device subsystem and a data recording device, which issue a command specifying a plurality of tracks (surfaces) in a rotary type memory device prior to a read or write instruction being issued from the data processing unit of higher rank to the rotary type memory device through a control unit; selects sequentially the plurality of individual tracks (surfaces) previously specified when executing a read or write command after the receipt of the command; and in this way can read/write continuously without wait time interruptions when data is discontinuous.

A method for controlling a rotating storage unit which parallelly transfers data between a plurality of heads of the rotating storage unit and a plurality of tracks of a record medium is disclosed. When there is a defective sector in any track, a non-defective sector which appears next to the defective sector as viewed in a sequence of logical arrangement of records in the sectors of the tracks is assigned as an alternative sector.

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Odawara, Japan

Mamoru Tohchi