Hitachi, Ltd.

Nippon T&t Corp.

Yuji Yamane

Toshimitsu Kaku

Soichi Isono

Yasushi Fukuda

Takashi Doi

Hitoshi Komatsu

Masaaki Kobayashi

Kiyoshi Honda

Mitsunobu Watanabe

Hiroshi Ide

Toshio Niihara

Satoshi Kawamura

Kiyoshi Matsumoto

Michio Miyazaki

Tsuneo Hirose

Shigenori Okamine

Kenji Tokumitsu

Nobuyoshi Izawa

Atsushi Takayasu

Yusuke Mizuno

Kunihiko Kizaki

Nobuhiro Matsumura

Toru Takeda

Multibeam optical disk record and reproduction apparatus and method, in which at least two light beams generated are concentrated in different positions of on recording tracks of a recording medium to record or reproduce data to or from the recording medium on the different positions at the same time. The light beams are moved independently of each other across the recording tracks so that any one light beam is movable during the recording or reproducing of data by another light beam. This allows parallel recording/reproducing with a plurality of light beams without producing areas unaccessed due to the jumps of the light beams.

Multibeam optical disk record and reproduction apparatus and method

A magnetic disk drive has magnetic disks having tracks and a number of sectors forming each track. The tracks have an ID few track format and the drive is divided into a plurality of notches. The drive also includes a memory and a defect sector list, sector replacement list, defect track list and replacement track list, each of which is stored in the memory. Defective sectors and tracks in each notch are slipped during formatting, and further defective sectors and tracks detected subsequent to the formatting are skipped. Spare sectors in the notch are provided in a spare region to accommodate the slipped and skipped sectors and tracks, respectively. The defective sector list is supervised as a two stage table to reduce the required memory size for maintaining the list and to decrease the time required for searching the list.

Rotational storage device

In a rotary type storage apparatus and a control method thereof, a plurality of concentric or spiral information tracks are set and also each of the plural information tracks is subdivided into a plurality of sectors along a circumferential direction, which constitute a plurality of information recording planes. Also, in this apparatus and method, there are provided a plurality of read/write heads employed at each of the information recording planes and accessible to the information tracks, and also a head drive mechanism for positioning these plural read/write heads to the information tracks. At least one of the plural information recording planes corresponds to such a recording plane where a substitution information track has been set, on which a substitution sector corresponding to a failed sector present at another information recording plane is recorded.

Rotary type storage apparatus and control method thereof

Method for controlling information recording in an information recording apparatus which includes a rewritable information record medium containing a data record area having a plurality of data recording blocks and an alternative area in which data to be written into a defective block in the data record area is written, and writing and reading of data to and from the blocks and erasing of data may be carried out, wherein, data is written into the respective blocks in the data record area on the information record medium, and if a data record error is detected, data to be written into the defect block is written into a block of the alternative area. When data is subsequently rewritten, contents of all blocks in the data record area to be rewritten, including the block previously determined to be defective, are erased and the new data is rewritten, and the content of the alternative area is erased. If a data record error is detected after rewriting, the data to be written into the defect block is written into a block in the alternative area.

Information recording control system reusing a defective area

A method of controlling a write operation for a rotating type recording medium in which a plurality of tracks are formed in such a manner that each track is divided into a plurality of blocks having respective addresses and each block is used as the information recording/reproducing unit, is disclosed. In this method, each block includes an information recording field and a flag field for indicating the presence or absence of recorded information in the information recording field, to follow the following procedure. That is, when a high-ranking apparatus specifies a block and issues a write instruction for writing information in the specified block, the flag field of the specified block is first checked, and then the first recording mode for immediately recording new information in the information recording field of the specified block or the second recording mode for recording new information in the information recording field of the specified block after an erasing operation has been performed for the above information recording field, is executed depending upon whether the flag field of the specified block indicates the absence of recorded information or the presence of recorded information.

Method of controlling write operation for rotating type recording medium

Growing community of inventors

Odawara, Japan

Yuji Yamane