Fujitsu Corporation

Kabushiki Kaisha Toshiba

Toshiba Storage Device Corporation

Hiroshi Mutoh

Yoshifumi Mizoshita

Takao Sugawara

Kiichirou Kasai

Masuo Ohnishi

Takenori Ohshima

Toyokazu Hamaguchi

Takashi Aikawa

According to one embodiment, a disk drive having a magnetic disk of the bit pattern media type is provided. The disk drive has a reproduction module configured to reproduce a signal from a measurement area provided on the magnetic disk and holding groups of phase-shift measuring bits, a measurement module configured to measure a phase shift that a write clock signal has with respect to data recording bits held in a data record area provided on the magnetic disk, when the signal reproduced by the reproduction module is indefinite, and a recording module configured to record data that corresponds to the data recording bits, by using the write clock signal adjusted by the phase shift.

Magnetic bit-patterned disk and disk drive

According to one embodiment, a disk drive comprising a magnetic disk of bit-patterned type is provided. The disk drive has a reproduction module, a measurement module, and a recording module. The reproduction module outputs a reproduced signal corresponding to the phase-shift measuring bits provided on the magnetic disk. The measurement module determines that the phase shift corresponding to the phase-shift measuring bits is the phase shift of a write clock signal if the reproduced signal is determined to be indefinite on the basis of the quantization value of the reproduced signal. The recording module records data corresponding to the data recording bits, by using the write clock signal adjusted by the phase shift.

Method and apparatus for measuring phase shift in a disk drive having bit-patterned media

According to one embodiment, a magnetic recording apparatus includes: an information recording module configured to record a predetermined number of lines of information with a predetermined length in an information recording region of a magnetic recording medium, each of the lines of information having a same recording start position with respect to a relative movement direction of the magnetic recording medium and a recording element, the each of the lines of information being provided with an overlaying portion of adjacent lines of information. The information recording module is configured to record clock information in one or a plurality of the lines of information.

Magnetic recording apparatus and magnetic recording medium

An electronic apparatus mounted with a disk unit, and a vibration and/or shock absorbing member which absorbs vibration and/or shock is provided between the disk unit and a lid member which covers a disk unit accommodating part provided in a housing of the electronic apparatus.

Electronic apparatus and disk unit mounting mechanism

A portable information processing apparatus which is a lap top type has a housing with a hard disk drive At the bottom side of the housing a first touch sensor is provided adjacent a corner and a second touch sensor is provided adjacent a corner which is at a diagonal side. Once the portable information processing apparatus leaves a table, output signals of the respective touch sensors and vary precisely. By comparing the output signals of the respective touch sensors and with a true value table memorized in a memory, it is decided whether the portable information processing apparatus has started dropping. If the portable information processing apparatus starts dropping, the hard disk drive enters the withdrawal mode.

Drop detection systems for portable information processing apparatus

A decoding circuit for a magnetic recording and reading system enables the implementation of an AGC loop with a relatively simple configuration and further enables easy clock extraction and high operating speed. The level setting system for setting the signal level to be taken as the value 1 in the decoding circuit is configured so as to comprise a variable-gain amplifier, a PR4 equalizer having characteristics capable of equalizing to a target PR4 equalization waveform, and a level detector which feeds the output signal back to the variable-gain amplifier as an AGC loop control signal to control the gain thereof. The detection system of the decoding circuit is configured so as to comprise a VFO which generates a system clock fs, and a decision feedback type decoding means in a decision section, which decodes data lines which appear at the output of the PR4 equalizer. In doing this, by configuring the decision feedback type decoding means so as to comprise a decoding means for even data lines and a decoding means for odd data lines, it is possible to reduce the system clock frequency to one half, thereby enabling an increase in the speed of decoding.

Decoding circuit for a read signal from a magnetic recording and reading

Maximum-likelihood decoding method and device

A Viterbi decoding system includes a characteristic estimator for estimating a characteristic of a system, and an equalizer for receiving an input signal from the system and for equalizing a waveform of the input signal so that an equalized waveform of the input signal is varied based on the characteristic of the system estimated by the characteristic estimator. A Viterbi decoder generates an output signal showing a maximum-likelihood path by using the equalized waveform of the input signal from the equalizer.

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Kawasaki, Japan

Hiroshi Mutoh