Kabushiki Kaisha Toshiba

Toshiba Electronic Devices & Storage Corporation

Yusuke Tomoda

Akihiko Takeo

Naoyuki Narita

Gaku Koizumi

Kenichiro Yamada

Tomoko Taguchi

Masaya Ohtake

Tomoyuki Maeda

Katsuhiko Koui

Nobuhiro Maeto

Hitoshi Iwasaki

Masayuki Takagishi

Susumu Hashimoto

Shuichi Murakami

Satoshi Shirotori

Kaori Kimura

Takeyori Hara

Takayuki Kawabe

Toru Watanabe

Koji Yano

Tatsuo Nitta

Takuya Matsumoto

Norihito Fujita

Mariko Kitazaki

Mio Okada

According to an embodiment, a controller executes a determination operation when a magnetic head passes over a servo sector during a write operation. In the determination operation, a first cumulative amount is calculated by accumulating, for a first section, evaluation amounts each corresponding to an amount by which the width of an adjacent track is narrowed due to the write operation, and determination is made as to whether the first cumulative amount is smaller or larger than a threshold value corresponding to a limit of error correction. When the first cumulative amount is determined to be larger than the threshold value, the controller interrupts the write operation and re-executes the determination operation after executing a rotational delay. The controller resumes the write operation when the first cumulative amount is determined to be smaller than the threshold value as a result of the re-executed determination operation.

Magnetic disk apparatus and method

A method according to one embodiment includes acquiring a result of quality inspection related to recording quality of first sectors included in a first storage area of a magnetic disk. The method includes calculating a first number being the number of sectors corresponding to a capacity obtained by subtracting a set capacity from an actual capacity of the first storage area. The first number is calculated based on the set capacity of the first storage area and a set value of recording density of the first storage area. The method includes selecting a second number of sectors from the first sectors based on the result of quality inspection. The method includes assigning addresses to a group of sectors that are not included in the second number of sectors among the first sectors. The group of sectors consists of sectors with the number corresponding to the set capacity.

Method and magnetic disk apparatus

According to one embodiment, a magnetic disk device includes a disk, a write head, an adjustment unit, and a write processing unit. The adjustment unit adjusts each of a first adjustment value, a second adjustment value, and a third adjustment value. The write processing unit can select shingled magnetic recording and perform write processing based on the first to third adjustment values. When the number of the plurality of tracks of the band is t+1 and the number of unused sectors among the plurality of sectors of the band is e. The adjustment unit adjusts the first to third adjustment values to establish ext.

Magnetic disk device

According to an embodiment, a magnetic disk device includes a magnetic disk, a magnetic head, and a control circuit. The magnetic disk has a plurality of first storage regions disposed in the radial direction. The recording method is changeable for each of the plurality of first storage regions. The control circuit operates such that, when having received a first command instructing to change the recording method of one first storage region out of a plurality of first storage regions, the control circuit changes the recording method of the one first storage region in accordance with the first command, and moves a magnetic head onto the second storage region before receiving a second command.

Magnetic disk device and method

According to one embodiment, a magnetic disk device includes a disk, a head including a read head that reads data from the disk, a write head that writes data to the disk, and an assist element that generates energy to enhance write performance by the write head, and a controller that selects and performs a first recording mode and a second recording mode different from the first recording mode, and selects and performs one of the first recording mode and the second recording mode according to an assist effect of the assist element.

Magnetic disk device and method of changing recording mode

According to one embodiment, a magnetic disk device comprises a magnetic disk, a magnetic head, a monitoring unit, and a control unit. When carrying out write of data to a first track, if an absolute difference between a light output monitored by the monitoring unit at the time of write and a light output monitored last time by the monitoring unit exceeds a predetermined value, the control unit controls a position of a write head and writes data again to the first track or a second track one track before the first track.

According to one embodiment, a magnetic disk device includes a disk having a first region in which a plurality of tracks is written and a second region that is positioned with a gap in a first direction of the radial direction of the first region, and in which a plurality of tracks is overwritten in the first direction, a head, and a controller that offsets part of a plurality of tracks which is overwritten in the second region in a second direction opposite the first direction to perform rewriting.

Magnetic disk device and rewrite processing method

According to one embodiment, a magnetic disk device includes a disk including a normal recording region written in a normal recording and a shingled recording region written in a shingled recording, a head including a write head and a plurality of read heads, the head moving on the disk by rotation about a rotation axis, and a controller which selects and executes the normal recording and the shingled recording, wherein a first minimum value of a cross track interval in the radial direction of the disk between two read heads in the plurality of read heads in the normal recording region is smaller than a first maximum value of the cross track interval in the shingled recording region.

Magnetic disk device and write processing method

According to one embodiment, a magnetic disk device includes a disk, a head including a main magnetic pole having a first end and a second end opposite to the first end in a radial direction of the disk, a write shield facing the main magnetic pole with a gap, and an assist element provided in the gap and at a position where a first distance between the first end and the assist element and a second distance between the second end and the assist element are different from each other, and a controller which controls a voltage applied to the assist element according to a shingled write direction in which a second track is overwritten on a first track.

According to one embodiment, a magnetic disk device includes a magnetic disk, a magnetic head including an assist part to assist recording of data into the magnetic disk, a controller configured to control the recording of data by the magnetic head based on a recording condition, and a memory configured to record a first threshold value used to define that an assist element included in the assist part is in a deterioration condition. Furthermore, the controller detects the condition of the assist element, determines whether or not the recording condition is changed based on the detected condition and the first threshold value stored in the memory, and changes the recording condition based on the result of the determination.

According one embodiment, a magnetic disk device includes a disk including a first region and a second region to which data before written to the first region is temporarily written, a head which writes data to the disk and reads data from the disk, and a controller which selectively performs conventional magnetic recording for writing a track at an interval in a radial direction of the disk and shingled magnetic recording for writing a track so as to overlap in the radial direction, and changes a cache data capacity of data which can be written to the second region in accordance with a first write capacity of data which can be written to the first region by the shingled magnetic recording.

Magnetic disk device and method of setting recording capacity

According to one embodiment, a magnetic disk device includes a disk, a head which writes data to the disk and reads data from the disk, and a controller which increases a first recording density of data to be written to a first sector having a first overwrite in the first sector and reduces a second recording density of data to be written to a second sector having a second overwrite different from the first overwrite, on a first track of the disk.

Magnetic disk device and method for adjusting write data

According to one embodiment, a magnetic disk device includes a disk, a head which writes data to the disk and reads data from the disk, and a controller which executes, in a first region segmented in a radial direction of the disk, at least one of conventional recording processing which writes a plurality of tracks with a space in between in the radial direction at a first linear recording density and shingled recording processing which writes a plurality of tracks on top of one another in the radial direction at a second linear recording density which is less than or equal to the first linear recording density.

Disk device having conventional magnetic recording region and shingled magnetic recording region of different linear density

According to one embodiment, a magnetic disk device includes a magnetic head, a magnetic disk on which a servo pattern used to position the magnetic head when data is to be recorded by means of the magnetic head is recorded, and a control section configured to set a recording condition for each predetermined unit of the magnetic disk on the basis of the servo pattern, and carry out recording of data on the magnetic disk according to the set recording condition.

Growing community of inventors

Kawasaki Kanagawa, Japan

Yusuke Tomoda