Kabushiki Kaisha Toshiba

Toshiba Electronic Devices & Storage Corporation

Kazuo Chokki

Akihiko Takeo

Takeyori Hara

Daisuke Sudo

Tatsuo Nitta

Tatsurou Sasamoto

Takuya Mori

Satoshi Shibata

Tetsuo Kuribayashi

Yasushi Ishizuka

According to one embodiment, a magnetic disk device includes a memory and a controller. The memory stores, for a predetermined track on a magnetic disk in the device, a counter, a counter threshold, and weights. The weights are individually set for divided areas of the predetermined track. The weights each have magnitude inversely proportional to a guaranteed number of times of data readout. When writing to an adjacent track of one or more of the divided areas is executed, the controller multiplies a number of times of writing by the weight corresponding to the one or more of the divided areas and adds the number of times of writing to the counter. When a numerical value of the counter reaches the counter threshold, the controller executes refresh to rewrite data in the predetermined track or executes reading for determining whether or not to perform the refresh.

Magnetic disk device and control method

According to one embodiment, a monitoring unit of a magnetic disk device monitors a supply voltage supplied to a plurality of actuators by a first threshold value at which power supply by back electromotive force of a motor is started, and a second threshold value that is larger than the first threshold value. In a case where the supply voltage is lower than or equal to the second threshold value and is higher than the first threshold value, a controller interrupts execution of processing of reading/writing data to a magnetic disk in at least one of the actuators according to a predetermined condition based on execution status of the processing in the actuators.

Magnetic disk device and data protection method thereof

According to one embodiment, a magnetic disk device includes a disk including a first region and a second region different from the first region, a head that writes data on the disk and reads data from the disk, an actuator that positions the head on the disk, and a controller which positions the head by driving the actuator and writes data in the first region and the second region with the head, a skew angle of the head with respect to a circumferential direction of the disk varying within a first angle in the first region, and varying, in the second region, from a second angle larger than the first angle to a third angle larger than the first angle and the second angle.

Magnetic disk device having two regions of different thicknesses

Magnetic head having difference skew angles at different regions on magnetic recording disk

According to one embodiment, a magnetic disk device is configured to read data from and write data to a magnetic disk using a magnetic head and provided with a control module that controls initial operation of the magnetic disk device according to initial firmware. The magnetic disk device includes a reader, a retainer, a blocker, and a switch. The reader reads control firmware stored in the magnetic disk. The retainer fixes a servo control amount for the magnetic head after the control firmware is read, and retains the magnetic head at a predetermined position above the magnetic disk. The blocker blocks input of an interrupt signal to the control module. The switch switches the initial firmware to the control firmware after the servo control amount is fixed and the input of an interrupt signal is blocked.

Magnetic disk device and control method thereof, and information processor

Growing community of inventors

Fujisawa Kanagawa, Japan

Kazuo Chokki