Sony Corporation

Hiroaki Yada

Takamichi Yamakoshi

Nobuhiro Hayashi

Hiroshi Kanno

Munekatsu Fukuyama

Noriyuki Yamamoto

Tetsuo Sekiya

Keitaro Yamashita

Hideo Suyama

Shigeyoshi Imakoshi

Masayuki Nakayama

Yoshiharu Shimano

Yutaka Soda

Satoru Seko

Junkichi Sugita

Toru Katakura

Keisuke Fujiwara

Disclosed herein is a magnetic disk apparatus such as a hard disk apparatus or a removable hard disk apparatus which allows switching of the speed of rotation of a magnetic disk while assuring a sufficient tracking control characteristic and a sufficient capacity. More concretely, a magnetic disk apparatus of the present invention, in which tracking of a magnetic head is controlled with reference to a plurality of servo areas formed at predetermined angular distances on a magnetic disk to access the magnetic disk, includes; the servo areas being formed in synchronism with a fixed clock signal such that reference patterns for tracking control are formed therein, a clock generation means for generating a clock signal common to the plurality of servo areas with reference to reproduction signals obtained from the servo areas, a tracking control signal generation means for generating a control signal for tracking control from the reference patterns with reference to the clock signal, a tracking control means for controlling tracking of said magnetic head with reference to the control signal, and a speed switching means for switching the speed of rotation of the magnetic disk.

Magnetic disk apparatus

A disk drive apparatus is provided which is capable of performing recording and playback processing of an AV data stream requiring real-time characteristics and processing in an operation mode suitable for battery driving. The construction is formed in such a way that a first operation mode in which a disk rotation speed is set to be low, to which error handling in which an upper limit of an error handling time is determined as an error processing method suitable for performing recording or playback of real-time continuous information is made to correspond, and a second operation mode in which the disk rotation speed is set to be high and in which retries can be performed repeatedly as an error processing method suitable for performing recording or playback of data having high reliability, can be set. Thus, lower power consumption of real-time continuous data processing in image recording and playback by battery driving, such as in a portable video camera, is realized.

Disk drive apparatus, and data processing method for use with disk drive apparatus

A disk recording/reproduction device ideal for processing audio-visual data streams requiring real-time characteristics. A disk device has an operating mode ideal for recording and reproduction of motion image and audio data requiring real-time continuity by limiting the time needed for error processing, and the host incorporating the disk device can easily monitor the real-time continuity. The host can specify the urgency of individual recording and reproduction instructions to the disk so that control of real-time continuity can be actively implemented in better detail. A means for assigning a total number to a plurality of simultaneously recorded or reproduced data streams as well assigning individual data stream numbers allows informing the disk device of the throughput required by the host.

Disk device having real-time and reliability recording modes

Disk device having real-time and reliability recording modes including simultaneously recordable channels set using commands

Disk device having real-time and reliability recording modes with buffer memory divided into predetermined data stream areas

An information recording medium and information processing device are provided so that recording medium-identifying ID information cannot be rewritten. Unique ID information specific to a recording medium is recorded in a servo zone, which is not a data zone in which data recording/reproduction can be performed. After the medium is installed in the disk drive, a user cannot rewrite the recorded ID information and can only read it. When information distributed via a network is stored in a storage device, the ID in the servo zone is verified so that the information can be stored in the storage device only when the storage device is properly licensed.

Information recording medium and information processing device

A disk drive for recording information on and reproducing information from a hard disk drive. The CPU of a host device controls the maximum allowable number of retries, or the maximum period of time allowed for retries, performed by the disk drive when an error occurs in a seek, record, or reproduce operation.

Method and apparatus for driving a recording medium, method and system for recording and reproducing information, and information supplying medium

Disk recording/reproduction device, and information processing system incorporating a disk recording/reproduction device thereof

A digital signal processing circuit having a memory for storing a digital signal obtained from a playback channel; a controller for writing the digital signal in the memory at a first rate and reading out the digital signal from the memory at a second rate lower than the first rate; and a processor for executing a desired process relative to the digital signal thus read out from the memory. The digital signal is written in the memory at a first rate by the controller and is read out therefrom at a second rate lower than the first rate. And then a desired signal process is executed relative to the digital signal read out from the memory. Therefore the required digital processing rate becomes lower than the transmission rate of the playback channel, whereby the transmission rate can be raised despite the condition that the time required for the desired signal process such as demodulation is rendered longer.

Method for reading and demodulating data at different rates

A magnetic disk device that has a sufficient tracking control capability and a sufficient capability, and has the rotational speed of a magnetic disk reduced to record moving-image information. A magnetic disk device accesses a magnetic disk with a magnetic head by effecting tracking control of the magnetic disk at predetermined angular intervals, each of the servo areas being formed in synchronism with a clock signal and having a reference pattern for the tracking control. The clock signal is generated by referring to a playback signal from a number of servo areas. Thus, a clock area in one servo can be shortened. The recording density of the magnetic disk is prevented from being reduced even if a number of servo areas area formed on the magnetic disk are effective to prevent the sampling frequency from being lowered. As a result, a sufficient tracking control capability and a sufficient recordable density can be achieved, and the speed of the magnetic disk can be reduced to record moving-image information.

Magnetic disk device

A clock generator applicable to a sample servo type magnetic disk drive is disclosed. Reproduced signals z(t) from a clock pattern are digitized by an A/D converter (,) before being fed to a phase comparator (,). An arithmetic unit (,) calculates an inner product of N sampled values and N weighting factors in a linear combination, and a D flip-flop (,) provides a phase comparison error signal f(&thgr;). The signal f(&thgr;) is converted by a D/A converter (,) to analog format before being supplied as a control signal to a VCO (,) via a loop filter (,). A clock signal CLK from the VCO (,) is controlled in phase so as to generate a clock signal CLK synchronized with the reproduced signals z(t). When the weighting factors are arranged so that their total sum becomes zero, the signal f(&thgr;) is free from adverse effects of DC elements superposed on the reproduced signals z(t), whereby a clock signal CLK in precise synchronism with the reproduced signal z(t) is obtained.

Clock generator and disk drive

A digital signal processing circuit comprising a memory means for storing a digital signal obtained from a playback channel; a control means for writing the digital signal in the memory means at a first rate and reading out the digital signal from the memory means at a second rate lower than the first rate; and a processing means for executing a desired process relative to the digital signal thus read out from the memory means. The digital signal is written in the memory means at a first rate by the memory control means and is read out therefrom at a second rate lower than the first rate. And then a desired signal process is executed relative to the digital signal read out from the memory means. Therefore the required digital processing rate becomes lower than the transmission rate of the playback channel, whereby the transmission rate can be raised despite the condition that the time required for the desired signal process such as demodulation is rendered longer.

Digital signal processing circuit

A digital magnetic reproducing apparatus comprises a reproducing head to reproduce data from a magnetic recording medium; an equalizer for shaping, by a partial response method, the waveform of the reproduced signal outputted from the reproducing head; and a decoder for decoding, by a maximum likelihood decoding method, the equalized reproduced signal obtained from the equalizer. The reproducing head employed in this apparatus is an MR (magnetoresistance effect) head which is capable of reducing the second harmonic distortion of the reproduced signal to be -25 dB or lower. Therefore the deterioration of the bit error rate that may result from the nonlinear distortion of the MR head can be further lowered within a sufficiently suppressed range in practical use.

Digital magnetic reproducing apparatus and digital magnetic

A highly reliable magnetic recording and playback apparatus utilizes an independent magnetic clock pattern region and a pattern set region to provide a common timing reference between a data recording region and its adjacent tracks. In the apparatus, the pattern set region provides a reference point so that the circumferential location of the magnetic pattern region can be determined. In one embodiment, the apparatus includes elements for playback of reproduced information recorded on a magnetic disk and an arrangement which provides for the generation of a data existing point clock.

Growing community of inventors

Kanagawa, Japan

Hiroaki Yada