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7636212 Magnetic disk drive with control of sense current of magnetic head  
An output of a magnetic head changes depending on the environmental temperature of a magnetic disk. In particular, under cold temperature conditions, an output of the head largely decreases mainly...
7630163 Storage device and seek control method  
A storage device includes a storage unit, a timer unit and a bias current applying unit. The storage unit stores, in advance, a value of a waiting time until application of a bias current to the...
7630159 Resistance mode comparator for determining head resistance  
An apparatus and method for determining a resistance of a magneto-resistive head. A current drawn by the head, in response to a fixed bias voltage across the head, is converted to a zero...
7620121 DC balance compensation for AC-coupled circuits  
A receiver has a first input port and a second input port both coupled to a differential amplifier through first and second input capacitors. A bias circuit coupled to the core side of the first...
7561357 Decoder with energization control circuit  
A multistage decoder circuit has an error reduction stage that includes an adaptation circuit. The adaptation circuit provides adaptable error reduction as a function of bit error rate. The...
7561373 Bias compensation method and appropriate bias force profile generation method, recording media and hard disk drive  
Provided is a method of compensating for a bias for efficient servo control of a hard disk drive, and optimally compensating for bias force based on the elapsed usage time of a hard disk drive, and...
7545596 System and method for WORM magnetic recording  
WORM safeguards are provided in a magnetic disk drive in which the disks are pre-magnetized or pre-recorded such that all magnetic domains on each recording surface are completely aligned pointing...
7545595 Magnetic disk apparatus having an adjustable mechanism to compensate write or heat element for off-tracking position with yaw angle  
A magnetic disk apparatus including: a disk holding data as magnetic information on a magnetic recording film; a head to perform writing and reading of the magnetic information; a rotary actuator...
7532426 Method for erase process on recording surface of disk and disk drive apparatus  
Embodiments in accordance with the present invention erase a desired area on a recording surface of disk or disk drive apparatus. According to an embodiment, a hard disk drive (HDD) performs erase...
7522365 Magnetic storage systems and methods allowing for recovery of data blocks written off-track with non-constant offsets  
A magnetic storage system includes a disk, a head, an actuator, a read channel, and a main controller. The main controller causes the head to read a data block of a selected track of the disk at...
7515371 Channel postamble extension to de-gauss pole tips  
A technique for de-gaussing the pole tips and yoke of a write transducer in a perpendicular magnetic recording system is provided. An oscillator in the read channel is configured to produce an...
7492539 Method for controlling a burnish cycle to minimize cycle time  
A method for controlling a burnish cycle to minimize cycle time is disclosed. MR sensor resistance measurements are used to monitor interference with the recording surface and when clearance is not...
7489471 Bias calculation, bias compensation, and bias table editing methods for HDD, recording media storing computer programs for executing the same, and HDD using the same  
In a hard disk drive (HDD), biases are measured across all zones of a disk, and nonlinear bias components are extracted. Upon a change in operational condition of the HDD, biases are measured at...
7486476 Magnetic data system having a shield biasing circuit with resistor coupled between the shield and substrate  
A magnetic data system according to one embodiment includes a head having a plurality of readers formed above a common substrate, each reader further comprising a shield and a sensor, a bias...
7486475 Magnetic data system having bias circuit with bias resistor  
A magnetic data system according to one embodiment includes at least one reader formed above a substrate, the at least one reader further comprising a shield and a magnetoresistive (MR) sensor. A...
7471491 Magnetic sensor having a frequency filter coupled to an output of a magnetoresistance element  
A magnetic sensor includes a magnetoresistance element having a peak of a thermal fluctuation strength of magnetization under a magnetic field having a certain frequency, a frequency filter...
7468852 Method of demagnetizing magnetic recording medium and apparatus for carrying out same  
Embodiments of the invention improve efficiency in alternating-current demagnetization of a magnetic recording medium. In specific embodiments, magnet fields in a direction slanting to an easy...
7460324 Head amplifier circuit with function for degaussing residual magnetism of recording head  
In a data-recording mode, a driver circuit supplies a recording head with a recording current corresponding to write data. In a degaussing mode, the driver circuit supplies the recording head with...
7450328 Method for recording bursts on a disk and related apparatus  
Embodiments of the invention provide a method for recording bursts on a disk and a related apparatus. In accordance with an embodiment of the invention, a method for recording bursts on a burst...
7440212 Method and systems for a highly error tolerant tape format  
Described herein are media drives for writing information to a media (e.g., a tape media), systems for storing information on a storage medium, and methods of writing information to a media. The...
7440213 Apparatus and method for controlling remnant magnetization in a magnetic recording head  
The present invention provides a magnetic writer. The magnetic writer comprises a write circuit, a write pole, a first write coil for inducing a first magnetic field in the write pole by a first...
7411756 Method and apparatus for write head demagnetization  
An apparatus and method for demagnetizing a write head of a disc drive. Under control of a clock oscillator, synthetic demagnetizing pulses are generated and applied to a writer-driver bridge. Also...
7411753 Method and apparatus for magnetization test of write head in a disk drive  
A disk drive of a perpendicular magnetic recording system has a magnetization test function, for testing the magnetized state of a write head. The disk drive is provided with a write driver and a...
7397622 Method and apparatus for improving servo stability in read heads while writing  
A method and apparatus for improving servo stability in read heads while writing is disclosed. In one embodiment, a magnetic storage device includes a disk surface and a transducer. The disk...
7382562 Preamplifier for use in data storage devices  
A preamplifier that includes an input configured to receive a preamplifier control signal and a fault detection circuit configured to monitor the preamplifier control signal received at the input...
7372653 Degauss waveform generator for perpendicular recording write head  
Embodiments of the invention provide a hard disk drive that is capable of performing degaussing promptly and properly and a recording method for use with such a hard disk drive. A hard disk drive...
7362530 Amplifier apparatus for use with a sensor  
An amplifier apparatus for use with a sensor includes: (a) a first and a second amplifying circuit segment coupled with the sensor and cooperating to effect substantially balanced handling of...
7339760 Integrated bias and offset recovery amplifier  
A preamplifier circuit is connected to a transducing head, and has integrated bias circuitry and offset recovery circuitry. The offset recovery circuitry is activated in response to a transition...
7330336 Dual polarity bias for prolonging the life of a heating element in magnetic data storage devices  
A magnetic read/write head having a heating element to induce a desired amount of thermal protrusion in the read and write elements to control the fly height of the read and write elements over a...
7319569 Servo writer  
A servo writer is provided, which applies DC magnetization to a zone of a magnetic tape that is in advance subjected to AC erasing and writes a servo signal onto the DC magnetized zone. The servo...
7280299 Recording method for magnetic recording medium, recording device for magnetic recording medium and magnetic recording medium  
After a DC erasing is performed in a direction by permanent magnets on a servo signal recording part, servo signals are recorded in the signal recording area of the servo signal recording part by a...
7269213 Waveform equalizer having a tap coefficient monitoring unit  
A waveform equalizer having a delay element of a feed-forward filter into which a reception signal is inputted is connected via a tap arrangement control switch to a weighting device The output of...
7265924 Servo writer with multiple servo write heads and a method of writing with the servo writer  
Disclosed is a servo writer in which a servo write head is easy to exchange, and which writes, to magnetic tapes, a servo signal from which a reading signal of the improved SN ratio can be...
7265926 High speed hard disk drive with symmetric writer  
A disk drive data storage system, comprising a magnetic disk a head for writing data to the disk, and circuitry for providing a first voltage (HWX) to a first node (N 1 ) and a second voltage (HWY)...
7265925 Recorded data deleting device for hard disk  
A recorded data eraser 1 defines therein a cavity 2 for insertion of a hard disk drive 20 in the cavity 2 and includes a coil 4 being arranged around the cavity 2 so as to encircle the...
7256954 Adaptive equalizer  
An adaptive equalizer comprising a variable filter which equalizes a digital input signal which is input in a time sequential order, an adaptive controller unit which updates a filter coefficient...
7253980 Technique for recording bias current glitches in magnetoresistive heads  
Circuitry for detecting and recording latches in read bias current may include circuitry for generating a reference voltage, a pair of current to voltage converters to convert the bias and...
7253978 Methods and apparatus determining and/or using overshoot control of write current for optimized head write control in assembled disk drives  
The invention includes a testing method which may be applied to at least one writer in a disk drive during the self-test phase to generate write parameters, focused on the Over Shoot Control (OSC)...
7251091 Current-sense bias circuit for a magnetoresistive head and method of sensing a current therethrough  
The present invention provides a current-sense bias circuit for use with a magnetoresistive head. In one embodiment, the current-sense bias circuit includes a voltage biasing portion configured to...
7224544 Method and device for recording data and erasing servo data  
After a DC erasing is performed in a direction by permanent magnets on a servo signal recording part, servo signals are recorded in the signal recording area of the servo signal recording part by a...
7215497 Adjacent track data guarantee processing method and disk device  
A guarantee processing method guarantees the data of an adjacent track in the case of a write fault when there is a possibility of an off track write. Even if a write fault is detected or an offset...
7209304 Systems, apparatus, and methods to determine thermal decay characterization from an equalized signal-to-noise ratio of a magnetic disc drive device  
The thermal decay of data written to a magnetic mass storage medium is determined by measuring and analyzing the time-domain equalized-signal-to-noise ratio (ESNR) and equalized...
7206155 High-speed, low power preamplifier write driver  
A write driver circuit ( 38 ) uses a matching resistors (R 0 , R 1 ) to match the impedance of the head ( 32 ) disposed between output nodes (OUTP, OUTN). Control circuitry (Q 4 , Q 5 , Q 6 , Q 7 ,...
7191083 Method and apparatus for calibrating data-dependent noise prediction  
Disclosed herein is an apparatus and method of calibrating the parameters of a Viterbi detector 138 in which each branch metric is calculated based on noise statistics that depend on the signal...
7187513 Differential magneto-resistive head pre-amplifiers for single polarity power supply applications  
Magneto-resistive (MR) head pre-amplifiers for single polarity power supply applications are presented. An exemplary pre-amplifier includes a bias network coupled to first and second input...
7173786 Magnetic disk drive apparatus and method for compensating characteristics of magnetic disk drive apparatus  
A magnetic disk drive apparatus includes a magnetic disk with a data region, a magnetic head located in a region of the magnetic disk other than the data region or outside of the magnetic disk...
7170700 Method of determining side track erasure in a disk drive  
A method of determining side track erasure in a disk drive having a disk and a transducer. A target track and one or more side tracks proximate to the target track on the disk are selected, and...
7167330 Over-writing data in a recording system  
A recording system stores recording cycle information identifying the parameters for recording user data on a particular data sector. During a subsequent operation, the recording system employs the...
7142388 Servo writer and servo writing process  
A servo writer according to the present invention is a servo writer which writes a servo signal on a servo band of a magnetic tape. It comprises a magnetic tape driving system in which a magnetic...
7130143 Apparatus, system, and method for measuring magnetoresistive head resistance  
An apparatus, system, and method are disclosed for measuring magnetoresistive head assembly resistance. A measurement module measures a reference voltage across a reference resistance while...