Hitachi Global Storage Technologies Netherlands B.v.

Sumie Takeda

Hiroyuki Oosawa

Katsumoto Onoyama

Akira Kojima

Shinichi Kobayashi

Nobuyuki Kitazaki

Nobuya Matsubara

Toshifumi Kumano

Iwao Oshimi

Yosuke Hamada

Mitsuharu Horiuchi

Embodiments in accordance with the present invention provide a disk storage device and a control method for the disk storage device, which are capable of precluding an off-track write resulted from stick-slip caused by thermal distortion. A magnetic disk device is provided with a magnetic disk, a head that makes a writing to the magnetic disk, and a temperature sensor that detects the temperature inside of the magnetic disk device. Moreover, the magnetic disk devicechanges determination requirements for use to make a determination whether or not to prohibit the writing by the head to the magnetic disk based on a measurement temperature detected by the temperature sensor and an amount of temperature change calculated using the measurement temperature.

Disk storage device and control method for the same

Embodiments of the present invention provide a magnetic disk device and a method for production thereof, the magnetic disk device being characterized in that the magnetic disk therein permits a plurality of tracks thereon to record correction data when necessary without decreasing its storage capacity. According to one embodiment, the magnetic disk device is characterized in that the magnetic disk has the first tracks and the second tracks formed thereon, the first tracks having servo data regions arranged cyclically, with a portion of a region between them being the correction data region and the remaining regions being the user data region, and the second tracks having the servo data regions arranged cyclically, with the region between them being the user data regions, and the multiprocessing unit (MPU) switches the servo extraction timing of the position information sampler depending on whether the track for servo reproduction by the magnetic head is the first track or the second track.

Disk drive device and method for production thereof

Embodiments of the present invention prevent occurrence of a write pole erasure in the event of a power failure within a magnetic disk apparatus of a perpendicular magnetic recording system. According to one embodiment of the present invention, a recording current is flowed through a magnetic head to record data in a magnetic disk. An occurrence of a power failure in the magnetic disk apparatus is detected. When a power failure has occurred, the recording head is demagnetized with power in case of a power failure. The recording head is unloaded after the recording head has been demagnetized. For the power in case of a power failure, back electromotive force of a spindle motor can be utilized. As a result, effects exerted on data recorded in the magnetic disk due to residual magnetism remaining in the recording head can be eliminated.

Recording method, unload method, and magnetic disk

Embodiments of the invention relate to diagnosing error-correcting retries of an upper system by using a disk drive under control of the upper system. In one embodiment, a microprocessor can operate in any of at least two operation modes. One is normal operation mode while the other is pseudo failure operation mode. Mode switching is made by a switch. Strictly, the pseudo failure operation mode includes three different operation modes: 1) pseudo logical error report mode in which a pseudo logical error is reported to the upper system without performing disk control; 2) pseudo component circuit failure mode in which a control circuit is forced to cause a failure by setting invalid control values to the control circuits; and 3) pseudo interface failure mode in which a pseudo interface failure in the system comprising multiple disk drives is reported by setting an invalid control value to the interface control circuit.

Magnetic disk drive with diagnosis of error-correcting retries

Growing community of inventors

Kanagawa, Japan

Sumie Takeda