Hitachi, Ltd.

Hitachi Global Storage Technologies Japan, Ltd.

Fujitsu Corporation

Fujitsu Semiconductor Limited

Hitachi Global Storage Technologies Netherlands B.v.

Fujitsu Vlsi Limited

Hitoshi Ogawa

Motoyasu Tsunoda

Shoichi Miyazawa

Eisaku Saiki

Yukari Katayama

Masatoshi Nishina

Terumi Takashi

Ryutaro Horita

Akira Kojima

Takashi Nara

Katsumi Yamamoto

Yasunori Kaneda

Katsuhiro Tsuneta

Tsuneo Hirose

Kiyoshi Honda

Satoshi Kawamura

Kazuhisa Shiraishi

Fukashi Ohi

Hideo Makabe

Seiichi Domyo

Yukie Miyazawa, Legal Representative

Atsushi Saito

Naoki Satoh

Hiroyuki Tsuchinaga

Hideaki Watanabe

Takushi Nishiya

Yoshiteru Ishida

Atsushi Okuyama

Yasushi Sakai

Kazuo Aoki

Eishirou Kawana

Kazuaki Usui

Koichi Ishida

Yukie Miyazawa

Yukie Hiratsuka

Soichi Isono

Tomoki Oura

A data communication method in a network including a plurality of communication apparatuses connected in the form of a ring, the network being logically broken at a given position, the method comprising: calculating transmission time between a sending apparatus and a granting apparatus granting control of a bus to the sending apparatus in each of a first communication environment in which data is transferred in a first direction on the network and a second communication environment in which data is transferred in a second direction different from the first direction; and changing the transfer direction on the network for each sending apparatus to a transfer direction that provides shorter transmission time on the basis of the calculated transmission times and performing data transfer.

Data communication method and communication apparatus

There is provided a data transfer method in an IEEE1394 system including a band request node and a transfer band management node. The method includes generating, at the band request node, a transfer request that can detect a data amount of transfer data and transmitting the transfer request from the band request node to the transfer band management node, determining, by the transfer band management node, whether a transfer band requested by the transfer request is ensured or not, notifying, from the transfer band management node, the band request node of the determination result, and transferring data from the band request node according to the determination result.

Data transfer method

A transceiver that reduces power consumption when data is transferred between devices in different modes. The transceiver is arranged in a first node and in a second node, which communicate between each other. A first control unit generates a first signal transmitted from the first node in predetermined time intervals during a first period that establishes an environment for communication between the first node and the second node. The second node transmits a second signal transmitted in response to the first signal. The first control unit generates a third signal upon detection of the second signal. A second control unit gradually decreases amplitude of the first signal based on the third signal to set the amplitude of the first signal to a predetermined amplitude so that the second node is receivable of the first signal.

Method for optimizing of communication signal

Embodiments of the present invention efficiently format long sectors, without decreasing the performance, in a magnetic disk drive in which servo sectors are radially formed at regular intervals, and make full use of the ECC performance that is enhanced by the long sectors. In one embodiment, a data format in each zone on a magnetic disk is completed by a plurality of tracks N (N is an integer, which is 2 or more). The storage capacity per track of the outermost radius zone Z#is 150 kB. In this zone, long sectors each having a length of 32 kB are formatted with the number of tracks per format N#=3. The storage capacity per track of the innermost radius zone Z#m is 80 kB. In this zone, long sectors each having a length of 32 kB are formatted with the number of tracks per format N#m=2.

Method for formatting data sectors on magnetic disk, and magnetic disk drive

In one embodiment, a write/read apparatus includes an external interface section for data input; an external interface section for data output; a memory for temporarily storing the data that is input through the external interface section for data input and written on the recording medium and the data that is read from the recording medium and sent to the outside through the external interface section for data output; an address generating section for generating unique addresses associated with physical block addresses of the recording medium; a flag generating section for generating flags for prohibiting overwriting of the data to be written on the recording medium; and a processing section for adding the unique addresses generated in the address generating section to the data that is stored in the memory and that is to be written on the recording medium. The data with the addition of the flags generated in the flag generating section and the unique addresses is written on the recording medium.

Write/read apparatus to control overwriting

A signal processing device having a feature of analog-to-digital converting a burst signal has a feature of selecting data bus to notify a disk control deviceof a conversion result via an NRZ data bus. The disk control deviceincludes means for storing the result of the analog-to-digital conversion of said servo positional signal. The positional signal of a head of the disk device is digitalized in an R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

Disk device and method of generating signal representing head

A disk drive apparatus mounting socket includes a socket portion which supports a disk drive apparatus, a lead portion which is connected to the disk drive apparatus supported by the socket portion, and a terminal unit which is electrically connected to the lead portion and to circuits on a board. A disk drive apparatus, which is connectable to an information processing unit, includes a connecting unit which connects the disk drive apparatus to the information processing unit, and an interface unit which controls the disk drive apparatus in response to a control signal, a data bus signal, and an address bus signal which are generated by the information processing unit and are inputted to the disk drive apparatus from the information processing unit via the connecting unit.

Disk drive apparatus and method of mounting same

The present invention provides a disk unit suitable for recording and reproducing time-series continuous data such as AV data. When data received as data to be written into recording medium is audio and/or video data, (this data is called AV data hereinafter), address informationidentifying a beginning sector of the recording medium in which the data has been written is registered in file control information. Also, it is determined whether or not the AV data is contiguous with AV data just before written. If it is contiguous, the beginning sector is not registered in control information storage means. Thus continuous data can be handled as one piece of data.

Recording/reproducing apparatus

A signal processing device for analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ data bus. The disk control device stores the result of the analog-to-digital conversion of the servo positional signal. The positional signal of a head of the disk device is digitized in a R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

Apparatus for recording and/or reproducing user data recorded on a record medium. The apparatus includes record encoder for converting original user data into encoded user data of a predetermined record code and as error correcting code generator for generating original error correcting code data for correcting an error with respect to the encoded user data. A write unit records the encoded user data and the error correcting code on the record medium. A read unit reads the recorded data and the reproduced data is error corrected so as to provide the original user data.

Apparatus and method for error correction

An information recording/reproducing system in which a host system making access to a magnetic disk apparatus can be limited to a specific one. A magnetic disk apparatus includes an authentication key generating block for generating an authentication key on the basis of physical characteristic(s) of the magnetic disk apparatus itself. The magnetic disk apparatus and the host system have, respectively, authentication key recording block for recording the authentication key and authentication data generating block for generating authentication data on the basis of the authentication key. Access from the host system to information of the magnetic disk apparatus is controlled based on the authentication data of the host system and the authentication data of the magnetic disk apparatus.

System for controlling host access to a storage device based on physical characteristics of the storage device

Defect management information of a disk apparatus is read efficiently. Pieces of defective track information, which each indicate existence of defective tracks for a group of a plurality of tracks, are stored being associated with physical track numbers. And, pieces of defect information on defective tracks are stored in predetermined groups. Further, pieces of pointer information that indicate start addresses of storage address for the above-mentioned predetermined groups are stored. When a processing means receives an instruction of read or write to a track of a storage medium, the processing means refers to a piece of defective track information based on the above-mentioned addresses. When existence of a defective track is indicated, the processing means refers to a piece of pointer information corresponding to the group relating to the referred piece of defective track information. Then, the processing means sequentially accesses the pieces of defect information from the storage area indicated by the above-mentioned piece of pointer information, to detect a piece of defect information of the track as the object of the instruction. Then, the processing means performs defect processing on the defective track based on the defect information detected.

Disk apparatus

A signal processing device for analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ data bus. The disk control device stores the result of the analog-to-digital conversion of the servo positional signal. The positional signal of a head of the disk device is digitalized in a R/W channel. Sampling for digital conversion is performed in only a window which is defined only in the vicinity of peaks of the positional signal. The values of peaks which are obtained by sampling are averaged by an averaging circuit. This enables the influence of noise occurred outside of the window to be eliminated. Although the noise in the window is sampled, its adverse influence is suppressed by the averaging processing.

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Yokohama, Japan

Hitoshi Ogawa