International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

Lenovo (Singapore) Pte. Ltd.

Takashi Kuroda

Hiroshi Uchiike

Katsuhiko Katoh

Yasuhiro Takase

Naoyuki Kagami

Fuminori Sai

Akira Tokizono

Hiroshi Uchida

Takahiro Saito

Masayuki Murakami

Tetsuo Ueda

Tetsuya Tamura

Kenji Ogasawara

Atsushi Kanamaru

Hiroshi Yanagisawa

Tatsuya Sakai

Yuzo Nakagawa

Yukio Fukushima

Nobuya Matsubara

Hiromi Nishimiya

Yuji Kigami

Haruo Andoh

Toshiaki Satoh

Kaoru Iseri

Yuhji Yokoe

Yuhji Kigami

Shunsuke Kobayashi

Emi Shimono

The present invention provides a data storage device comprising a disk storage medium containing user data in a plurality of sectors, a head for writing or reading the user data and error correcting means for correcting an error that occurs in the user data during the reading process. The error correcting means comprises a syndrome generator for generating syndromes on the basis of the user data contained in predetermined sectors, registers for storing the syndromes generated and an exclusive OR circuit for exclusive ORing the values stored in the registers.

Error correction method and apparatus for data storage device

A data storage device comprising a disk storage medium containing user data in a plurality of sectors wherein each of the plurality of sectors comprises a subdivision of a track, a head for writing or reading the user data and error correcting means for correcting an error that occurs in the user data during the reading process. The error correcting means comprises a syndrome generator for generating syndromes on the basis of the user data, a Euclid circuit, a chien search circuit and a verification circuit, and makes the error correction using a first error correcting code appended to each of a plurality of sectors and a second error correcting code appended to said sector for every block composed of a predetermined number of sectors.

Data storage method and data storage device

The exclusive OR (XOR) of user data (sector), user data (sector)and user data (sector)is taken to have the virtual user data, thereby giving rise to a correlation of the sectorsto, and its virtual user data is appended with Chaving a greater error correction capability than C, whereby an error uncorrectable with Cis correctable with C

Data storage device and data processing method

A servo system wherein a read head R detects a servo pattern that is written on a magnetic disk by a write head W. Position control of the write head W is exercised in accordance with the detected servo pattern, and the read head R detects a propagation pattern that is written on the magnetic disk by the write head W. Position of the write head W is corrected in accordance with the detected propagation pattern.

Servo information write method, servo control method, data storage device, and program

To improve the probability of error correction, thereby generating correct read data. Data is read from the same sector by a number of times and a majority decision is done in the same address, thereby the most frequently read value is regarded as the true data value in the address. For example, for an address 00, '00' is handled as a true data value.

Data storage apparatus, read data processor, and read data processing method

A method for registering a defect map within a hard disk drive is disclosed. A hard disk drive includes a recording disk, a head assembly, and a controller. Multiple sectors are formed on the recording disk, and the head assembly includes a head for reading/writing data from/to the recording disk. The controller, which controls the head assembly to read/write data from/to the recording disk, includes a defect sector positional information holding device and a sector identification device. The defect sector positional information holding device holds positional information of a defect sector disabled to read/write data therefrom/thereto the recording disk. The positional information includes the number of the defect sectors continued in a circumferential direction and in a radial direction of the recording disk. The sector identification device refers to the positional information of the defect sector so as to identify a target sector from/in which data is to be read/written when a read/write command is received from a host computer.

Method for registering a defect map within a hard disk drive

An improved system and method for implementing a rotary memory device, including a host system and a disk-shaped memory medium storing position information, or a servo address mark (SAM). If a head fails to read a valid SAM, a dummy SAM is generated to prevent an arm with a read/write head from entering a neutral state. If the normal state cannot be restored within a fixed number of intervals, the system goes into the emergency brake control mode. In this emergency brake control mode, the direction of the head is determined, and the VCM current is applied in such a way drive the arm in the opposite direction. Damage to the magnetic medium and subsequent data loss problems are reduced because the velocity of the head is reduced to a safe level.

System and method for implementing a rotary memory device

The present invention includes a method of reading and writing data on a recording medium, and a system including a disk drive apparatus and a disk drive apparatus controller. According to the method of the present invention, data can be read in the middle of a plurality of write commands provided that the addresses of the read/write data locations do not overlap. This method and system results in improved read/write times.

Method and system of reading and writing data by a disk drive apparatus

A system and method within a hard disk drive for transferring track sector information of a storage disk to a memory device. The system of the present invention includes a disk having multiple tracks, wherein each of the tracks includes at least one sector. The system further includes a memory device for storing sector identification data and user data. A drive data bus is utilized for transferring data between the storage disk and the memory. A controller is utilized to manages read and write operations to and from the storage disk, wherein the controller includes means for selecting either said user data or said sector identification data to be transferred to said memory device.

System and method for storing disk sector information

A storage device with a disk-shaped recording medium having servo areas in which servo sectors are recorded and data areas in which data sectors are recorded; a read/write head to read and write the data sectors, and to read the servo sectors on the disk-shaped recording medium; a head actuator to control the position of the read/write head; a storage controller to control data sector read and write operations by the read/write head; a servo controller to determine a position of the read/write head from the servo sector output read by the read/write head; a servo assist unit, separate from the storage controller, to calculate servo data for controlling the head actuator based on position information extracted by the servo controller and read/write head; and an interrupt generator to generate interrupt requests to the storage controller as determined by results of calculations by the servo assist unit.

Data storage device servo control apparatus and method

To realize simplification of the structure and high reliability in the disk drive. When a position of a target sector on a disk,is detected while skipping data sectors including a first region which is written using a first read/write clock (RDWTCLK) and a second region which is written using a second read/write clock, a controller,in a HDC,presets to a counter,an offset value which is based on the length of a sector to be skipped and a difference in the frequency between the first and the second RDWTCLKs and counts the first RDWTCLK fed from a CLK generator,of a channel IC,to detect the position of the target sector.

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Chigasaki, Japan

Takashi Kuroda