Hitachi Global Storage Technologies Netherlands B.v.

Hitachi Global Storage Technologies

Masaomi Ikeda

Kenji Ogasawara

Nobuyuki Kitazaki

Hirofumi Yanase

Atsushi Tobari

Masato Taniguchi

Hideaki Maeda

Nobuhiro Kuwamura

Takao Matsui

Yoshihiko Maeda

Satoshi Hashimoto

Atsushi Takeichi

Toshihiko Tsunokawa

Masahide Yamasaki

Akira Osaki

Masahiko Koizumi

Kohji Nakao

Junzou Noda

Takao Matusi

A method for dividing a data area on a disk into a plurality of concentric zones and determining a format for each zone so that data tracks in the zone have the same number of data sectors. The method includes dividing a data area into a plurality of zones with provisional boundaries. The method also includes determining a linear recording density for a selected zone. The method further includes selecting the number of data sectors per data track corresponding to the determined linear recording density from specified values. Moreover, the method includes resetting a boundary of the zone at a new boundary shifted from the provisional boundary according to a selected value.

Method for setting zone format of a disk for storing data and disk drive

Embodiments in accordance with the present invention provide a magnetic disk drive capable of achieving error recovery stably in a simple configuration in the event of thermal asperity (TA) and minimizing the error recovery time required, and a method for controlling the disk drive. According to one embodiment, if TA occurs, a cutoff frequency of a high-pass filter to which a data read signal is input is first increased and a loop gain of a low-order finite impulse response (FIR) filter connected in series to an FIR filter is also increased as high as possible. Next, a Viterbi decoder to which a signal is input from the low-order FIR filter provides feedback to the low-order FIR filter so that an input signal error becomes a minimum. Tap coefficients of the low-order FIR filter are thus optimized.

Disk drive

Embodiments of the invention prevent offtrack write that will be caused due to a head vibration in a storage device. In one embodiment, a hard disk drive (HDD) judges approval/disapproval of write of user data to a magnetic disk by using a read signal for user data in addition to servo data in write processing. Thus, a head vibration which cannot be precisely detected based on servo data is detected to prevent off-track write. More specifically, the HDD acquires a read back signal amplitude of a read element with respect to a user data sector within adjacent servo data during a write access phase, and detects a vibration from a maximum value MAX and a minimum value MIN of the read back signal amplitude to judge data write approval/disapproval.

Off track write protection for data storage device

Embodiments of the invention provide a magnetic disk drive that does not generate errors when information is read even if considerable time has elapsed after the information was written on the magnetic disk. In one embodiment, a magnetic disk has a storage area divided into a plurality of sectors ST. Time stamps TPcorresponding to each sector data mstored in the sectors STare stored in a time stamp recording medium. A processor controls the magnetic disk drive to read time stamps TPof sector data mstored in any sectors STof the sectors STand refresh sector data mselected based on an elapsed time calculated from information about the time when the time stamps are read and the time stamps TP

Magnetic disk drive and refresh method

The read/write offset between the read head and write head is used to determine the head width ratio between the read head width and write head width. The servo information is written onto the magnetic disk in accordance with the APC value and track pitch that are derived from the determined head with ratio.

Servo information write method, data storage device, and programs

Disclosed is a data storage device to provide servo patterns of a track pitch individually consistent with head characteristics (writing width, and reading width) in a recording medium of a hard disk device. The data storage device is provided with a disk having pitch information indicating a track pitch recorded in a predetermined area, and a head for scanning the disk to read the TPI ID and reading/writing data from/in the disk by being subjected to seeking control based on the TPI ID. The TPI ID is recorded as a part of a servo pattern in a TPI ID embedded area provided in an outer periphery of a data area of the disk.

Data storage device, recording medium, servo writing method, and data reading/writing method

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Kanagawa, Japan

Masaomi Ikeda