Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A portable information processing apparatus 10 which is a lap top type has a housing 11 with a hard disk drive 14. At the bottom side 11b of the housing 11, a first touch sensor 20 is provided adjacent a corner 22 and a second touch sensor 21 is provided adjacent a corner 24 which is at a diagonal side. Once the portable information processing apparatus 10 leaves a table, output signals of the respective touch sensors 20 and 21 vary precisely. By comparing the output signals of the respective touch sensors 20 and 21 with a true value table memorized in a memory, it is decided whether the portable information processing apparatus 10 has started dropping. If the portable information processing apparatus 10 starts dropping, the hard disk drive 14 enters the withdrawal mode.

Abstract: A portable information processing apparatus 10 which is a lap top type has a housing 11 equipping a hard disk drive 14. At the bottom side 11b of the housing 11, a first touch sensor 20 is provided adjacently to a corner 22 and a second touch sensor 21 is provided adjacently to a corner 24 which is at a diagonal side. Once the portable information processing apparatus 10 leaves from the table, output signals of the respective touch sensors 20 and 21 vary precisely. By comparing the output signals of the respective touch sensors 20 and 21 with a true value table memorized in a memory, it is decided that the portable information processing apparatus 10 starts dropping. In case that what the portable information processing apparatus 10 starts dropping, the hard disk drive 14 is in withdrawal mode.

Abstract: 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.

Abstract: A maximum-likelihood decoding method for decoding an input signal subject to intersymbol interference. An assumption is made of a measure of an interference caused by a future signal that is later in a sequence than an assumed data sequence, on the basis of a predetermined bits of sample values of said input signal that are earlier in a sequence than an assumed data sequence stored in an assumed path memory (104). An assumed sample value of said input signal by referring to this measure of interference. Maximum-likelihood decoding is conducted on said input signal, on the basis of this assumed sample value and a sample value of said input signal; a plurality of survivor paths are generated and stored in a path memory (102); data for the most likely one of survivor paths is output as a decoded data sequence.

Abstract: 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.

Abstract: A rail type universal parallel ruler device comprising a drawing board, a horizontal rail mounted on the drawing board, a horizontal cursor mounted shiftably on the horizontal rail, a vertical rail connected to the horizontal cursor, a vertical cursor mounted shiftably on the vertical rail, and a head connected to the vertical cursor, the improved rail type universal ruler device wherein a magnetic member is disposed on each of the cursors and rails for guiding the cursors and/or on a tail portion of the vertical rail and the side of drawing board for guiding the tail portion of the vertical rail, and magnetic force is caused to work between the magnetic members in a direction where the cursor is floated relative to the surface of rail and/or a direction where the tail portion of the vertical rail is floated relative to the surface of the drawing board side.