Kabushiki Kaisha Toshiba

Toshiba Electronic Devices & Storage Corporation

Akio Mizuno

Yasuhiko Ichikawa

Yutaka Arakawa

Hiroaki Inoue

Fubito Igari

Toru Takemura

Satoshi Shibata

Ryo Kobayashi

Takao Aoki

Taro Iketaki

Izumi Kawakami

Takanori Sumi

According to one embodiment, a magnetic disk device includes a disk, a head, a volatile buffer memory, a nonvolatile memory, a main power supply, and a control unit. The control unit includes a write processing unit, a management unit, a data protection processing unit, a counter, and a determination unit. When the determination unit determines that a difference has reached a threshold, the management unit returns write data of the volatile buffer memory, which is original data of write data of a track in which a count value becomes a maximum value among tracks, to a protection target.

Magnetic disk device

According to one embodiment, a magnetic disk device includes a disk including a first region and a second region, a head configured to record write data to the disk, a buffer configured to store the write data up to a first capacity, and a controller configured to obtain a first processing amount based on a time to save the write data to the first region by the head and a second processing amount improved by saving the write data from the buffer to the first region, compare the first processing amount with the second processing amount, and determine whether the write data should be saved to the first region, based on a result of the comparison between the first processing amount and the second processing amount.

Disk device and control method that controls amount of data stored in buffer

According to one embodiment, a disk controller includes a receiver, a read-modify-write controller, and a wait controller. The receiver receives data in units of predetermined data length. The read-modify-write controller performs a read-modify-write operation when the receiver receives the data to write the data to a sector on a disk medium the rotation of which is controlled. The sector is longer than the predetermined data length. The wait controller delays the start of the read-modify-write operation by the read-modify-write controller for within the time which the disk medium takes to rotate once and which is substantially the same as the time required to control the read-modify-write operation.

Disk controller, disk drive device, and disk control method

According to one embodiment, the controller controls a data refresh operation. The data refresh operation comprises a refresh-data read operation of reading L blocks of data by a head from a track to be refreshed on a disk, a data backup-write operation of writing the read data by the head to a backup-track on the disk, and a refresh-write operation of writing the read data by the head to the track to be refreshed after the backup-write operation. The controller sets the number L of blocks to a value that satisfies conditions for completing the backup-write operation and the refresh-write operation within a time corresponding to N revolutions of the disk from completion of the refresh-data read operation.

Magnetic disk drive capable of refreshing data written to disk and data refresh method

A CPU determines whether or not the disk access range designated by a read/write command from a host contains a defective sector. If the disk access range contains a defective sector, the CPU suspends disk access when a head has reached the defective sector. In this state, the CPU activates a buffer access circuit. The buffer access circuit copies data between an area of an alternate sector buffer and data buffer. The area of the alternate sector buffer stores data corresponding to the data written in the alternate sector allocated to the defective sector reached by the head.

Apparatus and method for accessing a disk containing an alternate sector

Disclosed is a method of access control for a disk drive whereby an access operation for, particularly, sequentially and alternately executing accesses is supported. A CPU of the present disk drive sequentially and alternately executes accesses to a plurality of data tracks on a disk in response to an access request generated from a host system. During the access operation, the CPU secures time for a look-ahead operation, the time corresponding to the difference between transfer rates. Thus, sequential and alternate access operation in which the number of seek operations can be reduced can be realized.

Method and apparatus for access control in a disk drive

Magnetic recording/reproducing apparatus in which partially-missed data has priority to be transferred to the host system as dummy data over optional data in order to minimize a frame skipping area caused by the dummy data, the dummy data which is used for executing data reproduction having sufficient continuity for a viewer.

Data reproducing unit, data reproducing method of the same, and a magnetic recording/reproducing apparatus

Servo sector numbers for identifying servo areas are recorded at predetermined positions in the respective servo areas on a disk. A plurality of data sectors are arranged between the respective servo areas. When a data sector is to be accessed, a servo circuit extracts a corresponding servo sector number. A CPU generates a data sector pulse at a timing corresponding to the start position of the data sector on the basis of the extracted servo sector number. The start position of the data sector is accurately detected in accordance with this data sector pulse, thereby reliably performing data access.

Growing community of inventors

Ome, Japan

Akio Mizuno