Hitachi, Ltd.

Hitachi Maxell, Limited

Zenji Tsutsumi

Takeshi Maeda

Yoshito Tsunoda

Yoshihisa Kamo

Shigeru Nakamura

Kazuo Shigematsu

Hiromichi Fujisawa

Shunichi Torii

Masahiro Ojima

Toshinori Sugiyama

Masahiro Takasago

Akito Sakemoto

Hiroshi Yasuoka

Motoo Uno

Yasumitsu Mizoguchi

Hiroshi Maejima

A fast access high capacity data storage system and method are disclosed, the data storage system including a disk-based storage system employing a plurality of storage surfaces. Selected storage surfaces have a plurality of independently controlled data access heads in data communication therewith, and circuitry is provided for allowing concurrent data transfers through the plurality of data access heads. Performance is further improved by monitoring frequently accessed data records and transferring them to a copy recording surface or recording surfaces less frequently used, and by moving a data access head of the plurality of data access heads to other recording surfaces to decrease access bottlenecks. The storage system further includes circuitry for averaging at least one of record length data, transfer timing data, access timing data and address data.

High capacity data storage method and system using independently

Optical information recording/reproducing system including novel

A method of detecting a light spot control signal is disclosed in which, when information is reproduced from an optical disk for optically recording information, a signal level obtained at a high-reflectivity portion of the optical disk is taken out of a signal reproduced from the optical disk, and is used as a control signal, which controls a light spot so that it tracks information stored in the optical disk.

Method of detecting light spot control signal

The difference between the two gain control signals for two amplifiers which correspond to two of a plurality of read heads which have the maximum and minimum output levels is detected. Whether or not the difference exceeds a predetermined value indicates an abnormality of the outputs of the read heads due to dust adhering thereto.

Information reading device for a multitrack storage device

Growing community of inventors

Kokubunji, Japan

Zenji Tsutsumi