Kabushiki Kaisha Toshiba

Toshiba Electronic Devices & Storage Corporation

Yosuke Kondo

Kenji Yoshida

Kana Furuhashi

Kazuya Takada

Syosuke Maruyama

Akihiro Yamazaki

Kohsuke Harada

Eric R Dunn

Kazuhito Ichihara

Takashi Matsuo

Hidetoshi Tsuneda

According to one embodiment, a magnetic disk device includes a read control system that extracts scrambled data from media data read from a medium and inspection data associated with a seed value at the time of write, generates inspection data for data extracted from the media data, obtains from the inspection data and inspection data extracted from the media data, a seed value associated with both, compares this seed value with the seed value expected by the controller, and evaluates, when the comparison result is a mismatch, the data as an error, whereas when match, descrambles the data extracted from the media data using the seed value.

Magnetic disk device

According to the embodiment, an HDC receives a plurality of data segments from a host, and executes generation and addition of a first code and output of a data segment to which the first code is added to each data segment. An HDC calculates exclusive OR with respect to the first codes, and outputs obtained first information. The RWC performs data conversion and calculation of exclusive OR on the plurality of data segments to which the first code is added, and outputs the plurality of data segments after the data conversion and a track parity obtained by the calculation of the exclusive OR. The RWC acquires the first code from the plurality of data segments. The RWC calculates exclusive OR with respect to a group of the second codes which are the acquired first codes to acquire second information. The RWC compares the first information with the second information.

According to an embodiment, each of a plurality of controller chips included in a magnetic disk device includes a buffer control circuit and an arbitration circuit, and controls a corresponding one of a plurality of actuator systems. The first controller chip is connected to a buffer memory via the buffer control circuit included in the first controller chip, and is connected to the second controller chip. The second controller chip is connected to the first controller chip and the third controller chip. The arbitration circuit included in the second controller chip performs arbitration between data transfer between the third controller chip and the first controller chip and data transfer between the first controller chip and an actuator system controlled by the second controller chip among the plurality of actuator systems.

A magnetic disk device includes a magnetic disk, which includes, in a track, a plurality of first sectors each recording user data and a second sector recording parity data for restoring the user data recorded in the first sectors, and a disk controller configured to read data from a plurality of sectors including the first sectors and the second sector based on an instruction from a host, and to detect whether there is an error in each of the first sectors when the user data is read from the first sectors. The disk controller continues reading the data recorded in the plurality of sectors even when an error is detected in one of the first sectors by the disk controller.

Magnetic disk device and method of continued reading of sectors of magnetic disk device even after an error is detected in one of the sectors

A hard disk device accepts logical block addresses (LBAs) from a host. The hard disk device includes a disk having a plurality of physical sectors from which data is read and to which data is written, and a processor configured to perform read and write operations on the disk in response to read and write commands from the host that designate LBAs. The processor, in response to a request for initialization, does not perform any write operations on the disk, and generates a new mapping of LBAs to the physical sectors for a current generation based on unusable sectors detected during a previous generation, and tracks differences in correspondence between LBAs and the physical sectors between the current generation and the previous generation.

Hard disk device and method of controlling the same

A magnetic disk device includes a plurality of tracks and a controller. The controller receives write data to be written to a first sector of a track, generates a first data string based on the write data and a logical identifier for the first sector, attempts to cause the first data string to be written to the first sector, determines whether a write error has occurred while the first data string is written to the first sector, generates a second data string based at least in part on the first data string, and in response to determining that no write error has occurred while the first data string is written to the first sector, writes a parity data string that is based at least in part on the second data string to a second sector of the track that stores parity data for the track.

Magnetic disk device configured to write parity data that is based on data being written to a parity sector when no error is detected in writing the data being written

According to one embodiment, a data recovery circuit includes an XOR operation unit, an erroneous bit position inferring unit, an error factor inferring unit, and an error provisionally determining unit. The XOR operation unit performs a bitwise XOR operation on M data sequences of N bits, where M and N are integers of two or greater. The erroneous bit position inferring unit infers an erroneous bit position based on the XOR operation result. The error factor inferring unit infers the inverted direction of the erroneous bit. The error provisionally determining unit performs bit inversion in the erroneous bit position, the direction of the bit inversion being opposite to the inferred inverted direction.

Data recovery circuit, semiconductor storage device, and data recovery method

A storage controller includes a control unit and an interface. The control unit, when write data input as data to be written onto a magnetic disk includes a bit string of a first pattern, inverts one or more bits of the bit string. The write data includes a redundancy bit string used for data error correction. The interface outputs write data including bit inverted by the control unit.

Storage controller, storage device, and method

A magnetic disk apparatus includes a disk and a controller. The disk includes a plurality of tracks including a first track and a second track that is different from the first track. A plurality of data sectors are located on the tracks. The data sectors include short data sectors and long data sectors, each including a plurality of short data sectors. If the controller accesses a long data sector located at an end of the first track, the controller first accesses a short data sector of the long data sector at the end of the first track, and then accesses a short data sector of the long data sector at the beginning of the second track.

Magnetic disk apparatus and method for accessing data sector

According to one embodiment, a chien search device includes n operation units configured to perform exclusive-OR operations, for each of the coefficients. Further, the chien search device includes first register configured to hold operation results of a highest order operation unit, for each of the coefficients. Furthermore, the chien search device includes exclusive-OR operation unit configured to perform exclusive-OR operations of the results of the first exclusive-OR operations of the highest order operation unit, for each of the coefficients. Moreover, the chien search device includes second register configured to hold operation results of the exclusive-OR operation unit, for each of the coefficients. The respective operation units reduce the number of stages of exclusive-OR operations by using the second register values.

Chien search device, storage device, and chien search method

According to one embodiment, semiconductor memory device and a random number generator includes A semiconductor memory device includes: a semiconductor memory, a random number generatorgenerating a random number sequence, and a data writing unitstoring data in the semiconductor memoryusing the random number sequence. The random number generatorincludes: a random number generating unit generating an M-bit random number sequence; a coefficient selecting unit outputs a first coefficient or a second coefficient to the random number generating unit; and a bit selecting unit which outputs the random number sequence obtained by selecting N bits from M-bit random number sequence output from the random number generating unit.

Semiconductor memory device and random number generator

According to one embodiment, storage device, a CRC generator device and a CRC generation method includes A storage device includes: a storage unit, a data reading unit, and a CRC generation device. The CRC generation deviceincludes a CRC generation unitgenerates a first CRC value; an ECC unitdetects an error sequence in a reverse order; a CRC reverse operation unitcalculates a CRC reverse operation result for the error sequence; a CRC generation shift register groupto retain CRC conversion information; an error sequence CRC generation unitobtains a second CRC value; and an XOR unitobtains a CRC value for an errorless recording sequence.

Storage device, CRC generation device, and CRC generation method

According to one embodiment, there is provided a controller including an interference cancelling module, a boosting module, and a decoding module. The interference cancelling module generates a first correction signal by cancelling an interference component from an adjacent track in a signal read from a target track of a disk medium. The boosting module generates a second correction signal by boosting a low frequency component of a signal corresponding to the first correction signal. The decoding module decodes a signal based on the second correction signal.

Controller, disk drive, and read-back signal processing method

According to one embodiment, an encoder/decoder apparatus includes an encoder module, a decoder module, and a transposing module. The encoder module is configured to generate a Hamming code from the input data, in accordance with a check matrix having a specific regularity. The decoder module is configured to detect an error position in the output data composed of the Hamming code, in accordance with the check matrix. The transposing module is configured to perform a transposing process of transposing some of the columns of the check matrix, while maintaining the regularity of the check matrix, and to change the error position in accordance with the transposing process, during the decoding process.

Data storage apparatus with encoder and decoder

According to one embodiment, a decoder device includes a decoder configured to decode a to-be-decoded sequence by performing an iterative decoding process and to perform a parity check of a decoding result using a check matrix, a detector configured to detect that the to-be-decoded sequence is a non-code word based on a parity check result for each row of the check matrix by the decoder, and a controller configured to control the decoder according to a detection result of the detector.

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Fujisawa Kanagawa, Japan

Yosuke Kondo