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6314433 Frame-based heroic data recovery  
Frame-based heroic data recovery on data retrieved from mass storage in which identifiable blocks have been detected to be corrupt. Logical sets of blocks are configured into frames. The invention...
6313963 Viterbi detector with partial erasure compensation for read channels  
A system and method for partial erasure compensation for a read channel is disclosed. The method comprises receiving a signal at a first state, the first state having a branch extending to each of...
6310739 Method and system for detection recording media defacts  
A discrete-time filtering method for identifying defects in a magnetic medium, comprising the steps of: reading data signals from at least a portion of the medium; sampling the data signals to...
6310741 Magnetic disk apparatus with data track reassigning function  
When the amount of position error PE of a magnetic head meets the condition of Ewf>PE>=Eww for two threshold values Ewf and Eww meeting Ewf>Eww, the track is registered in the track information...
6307698 Magnetic tape read apparatus and error identification method  
An amplitude comparator compares to one another amplitudes of data items, which have been read by read heads and amplified by amplifiers. An error identification circuit detects a read level...
6304405 Method and apparatus for controlling read and/or write operations of a disk drive device during start-up  
A method and apparatus for reducing the amount of time from a power-on status to a ready status of a hard disk drive device. In response to a power-on of a disk drive device, the rotation of a data...
6304397 Magnetic recording/reproducing apparatus with rotary drum with magnetoresistance head for transducing DC-free code signals  
A helical scan magnetic recording/reproducing apparatus incorporating an MR head to serve as a reproducing magnetic head is arranged to convert data which is recorded on a magnetic tape into data...
6304396 Arrangement for reading information from a magnetic record carrier  
An arrangement is disclosed for reading information from a record carrier. The arrangement comprises a read head having at least one magneto-resistive element (Rmr), a first transistor (Tr1) and a...
6301679 Sync byte padding  
A method and system that map the defects on the storage media of a disc drive. The method and system calculate the position of the defect and from that position determine the sector that must be...
6297920 Information reproduction apparatus  
An information reproduction apparatus uses a block storer to store blocks read by a reproduction head tip, and uses an error detector to detect errors in the blocks. The information reproduction...
6297925 Method for eliminating wiggle of magnetic head in hard disk drive  
A method for eliminating a wiggle of a magnetic head in a hard disk drive includes the steps of moving a first magnetic head to a parking area when wiggle is generated in the first magnetic head...
6295175 Apparatus for recognizing spin valve head failure due to pin layer magnetic field offset  
When a pin layer magnetic field offset judgment unit judges that a magnetic field in a pin layer of a spin valve head through which a sense current flows in the interference direction has been...
6292317 Method and apparatus for performing a flaw scan of a disk drive  
The present invention is directed to the high speed detection of flaws in a disk drive. In one embodiment, a preamplifier simultaneously receives and processes read signals provided by multiple...
6292912 Disk drive having built-in self-test system for characterizing performance of the drive  
A disk drive has a normal mode of operation and a built-in self-test (BIST) mode of operation for producing a sequence of channel metrics {Γn }. The disk drive includes a recording surface having ...
6292316 Detection and characterization of defects on surfaces of magnetic disks  
A magnetic disk tester which also incorporates a sensor such as an AFM or MFM is described. The device is able directly and quickly to detect and characterize sub-micrometric defects on the surface...
6289483 Read retry method in disk drive  
A method for retrying a read operation upon detecting a read error of a disk drive is disclosed. The method includes the steps of decreasing the revolution rate of a disk until the read error is...
6289484 Disk drive employing off-line scan to collect selection-control data for subsequently deciding whether to verify after write  
A disk drive that includes a disk defining a multiplicity of sectors operates in accord with a method comprising the steps of providing a firmware-controlled state machine which can be in any of a...
6282040 Write pass identifier  
A method of encoding data to distinguish between new data and incompletely erased old data when restoring the data from a magnetic tape storage device comprises: arranging a byte stream of user...
6282501 Disk drive testing  
The invention includes a method and integrated circuit for testing a disk drive. The invention internally generates test inputs to the host interface in the disk drive. The test inputs emulate the...
6282039 Scratch protection in tape data storage system  
A method of redundancy coding of user data received from a host apparatus and storage of said coded data on a magnetic tape data storage medium comprises inputting a byte stream of user data into a...
6268973 Generating appendable points in encoded data  
In a tape drive, a host interface receives from a host computer host data to be compressed and stored to tape. The host interface and also receives commands to create appendable points in the...
6266199 Method of apparatus to characterize and limit the effect of disk damage in a hard disk drive  
A method and apparatus for monitoring the quality of the readback signal of data written on a magnetic recording disk in a disk drive and for limiting data loss due to physical damage at a...
6266202 Closed loop write verification in a disc drive  
An apparatus and method for performing real-time, closed loop write verification in a disc drive having a rotatable magnetic disc and a head having read and write elements. During a write...
6266201 Multiple channel rewrite system  
In a data recording system utilizing multiple channels and data blocks wherein the data blocks are read subsequent to being written so as to check for errors, the data blocks are rewritten...
6260170 Method for controlling memory and digital recording/reproducing device using the same  
A method and apparatus for controlling a memory to record data received at random rate into a fixed rate and to reproduce the data recorded in a fixed rate includes a shuffle memory with a...
6256158 Calibrating write pre-equalization in a data storage device  
A method is described of calibrating a write pre-equalization circuit in the write channel of a magnetic data storage device which maximizes the rate at which the write channel can write to a data...
6256161 Echo cancellation for disk drive read circuit  
Echo cancellation is provided in a disk drive circuit having a transducing head connected to a preamplifier circuit by an electrical interconnect with a first time delay, a first interface between...
6256159 Method and circuit for dibit detection  
A circuit (10) and method for dibit detection in a mass data storage device includes concurrently operating magnitude (16), polarity (18), and peak value (20) qualification circuits. The magnitude...
6252731 Parametric optimization using disc drive read channel quality measurements  
An apparatus and method are disclosed for optimizing the operational performance of a disc drive having a head adjacent a rotatable disc, a servo circuit which controls the position of the head and...
6249890 Detecting head readback response degradation in a disc drive  
Method and apparatus for predicting future failure of a disc drive head from degradation in a head readback response characteristic, such as electrical resistance, readback signal amplitude,...
6249394 Method and apparatus for providing amplitude instability data recovery for AMR/GMR heads  
A method and apparatus for providing amplitude instability data recovery for AMR/GMR heads during amplitude loss using MSE and/or amplitude envelope detection procedures. The method includes (a)...
6246537 Recording medium, method and apparatus utilizing circular logical block address association  
A disc-shaped recording medium for magnetically recording information signals, in which logical block addresses are associated with the recording tracks on the disc in such a sequence in which the...
6239931 Technique for reassigning data sector by detecting soft defect  
A data sector reassigning technique in a hard disk drive detects of a soft defect in a hard disk drive having a plurality of data sectors and an error correction capability. An error rate is...
6233108 Storage device with the ability to check for defects in same  
All storage areas constituting a storage medium are checked for defects by successively reading and writing data. If an error that has occurred owing to the checking operation is an error for which...
6229660 Method and apparatus for reading information recording field of hard disk drive to enable reliable adjustment of automatic gain control and phase-locked loop  
A technique for reading an information recording field in an information recording disk of a hard disk drive determines whether a read error is generated during a reading of the information...
6229661 Digital data recording and reproducing apparatus and digital data reproducing apparatus  
This invention provides a digital data recording and reproducing apparatus and a digital data reproducing apparatus for recording data to a recording medium which can handle instrumental data as...
6229659 Methods and apparatus for storing data and auxiliary information  
Data are stored on magnetic tape along successive tracks extending obliquely across the tape, in each of several areas including a lead-in area, a data area and an end-of-data (EOD) area. Each...
6226140 Shock detector in a disk drive servo control system  
A direct access storage device (DASD) servo control system detects a servo pattern recorded in multiple cells of a servo sector and compares the cell-to-cell readback signal independently of the...
6222693 Re-recording/re-producing device for magnetic tape and head cleaning  
A re-recording/re-reproducing device cleans both the magnetic tape and head of dregs which cause errors in writing and reading. A magnetic head records and reproduces input digital data to and from...
6219192 Method and apparatus for the compensation of an additive signal in a data signal  
The method and apparatus have application to the compensation of transient signals produced on reading a data storage device with a magneto-resistive head due to thermal contact with asperities on...
6208477 Hard disk drive having a built-in self-test for measuring non-linear signal distortion  
In a hard disk drive, a semiconductor chip includes a circuit used in a built-in self test ("BIST") to determine an amplitude of a dibit echo for characterizing nonlinear distortion of a readback...
6208476 Data recording device and method for recording data on a magnetic tape with error correction  
A data recording device for recording data on a magnetic tape by means of a rotational head. A buffer memory buffers the data received through input/output unit, and a controller controls the data...
6201651 Circuit for reproducing data and apparatus for reading data out of a magnetic disc based on calculated frequency cut off  
An apparatus for reading data out of a magnetic disc includes a circuit for reproducing data, the circuit having a high-pass filter having a cut-off frequency which is a maximum in the range that a...
6201654 Method and apparatus for recording digital signal  
Method and apparatus for recording and reproducing a digital signal, by which time information specifying to each packet an interval relative to the adjacent packet is added to a digital signal of...
6201655 Rotational storage device  
A magnetic disk drive has magnetic disks having tracks and a number of sectors forming each track. The tracks have an ID few track format and the drive is divided into a plurality of notches. The...
6198582 Efficient run length limited code with short interleaved constraint  
An encoder and a method of encoding successive data words into successive code words for transmission through a channel is provided. The encoder divides each successive data word into first and...
6194895 Asymmetry measuring apparatus and method  
An asymmetry measuring apparatus is provided which comprises: dividing means for dividing read data output from a read data generator in data storing means; a DC level converter for converting the...
6195219 Method and apparatus for improving a thermal response of a magnetoresistive element  
A method and apparatus for improving a thermal response of a (magnetoresistive) MR element. In one embodiment, the thermal response is improved by reducing the heat transfer from the MR element to...
6191909 Polling a preamplifier within a disk drive to remotely determine pre-established parametric values  
A system for polling a preamplifier unit to remotely determine pre-established parametric values in a disk drive is disclosed. The disk drive comprises a controller, a preamplifier, and a plurality...
6191905 Magnetic disc apparatus  
The present invention provides a magnetic disc apparatus comprising: a magnetic disc and a signal processor having functions of (i) setting measurement points at an interval which is smaller in the...