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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...
6188533 Data reading method, recording medium used in the method and storage apparatus using the method  
Desired data recorded in a recording medium is read as a result of a head scanning a desired track, track tracking information for detecting the amount of displacement of said head with respect to...
6185058 No-ID data storage disk drive data sector formatting system and method  
A data storage disk drive system uses a no-ID disk architecture. The disk is formatted by mapping the disk in the desired format and allocating the defective regions to defective sectors. The list...
6185175 Sampled amplitude read channel employing noise whitening in a remod/demod sequence detector  
A sampled amplitude read channel is disclosed for disk storage systems (e.g., magnetic or optical) comprising a sampling device for sampling the analog read signal emanating from the read head...
6181499 Method and apparatus for testing the digital read channel circuit of a data storage device  
A method and apparatus for testing digital read channel circuits within a data storage device includes a digital read channel circuit coupled to a simulated impulse response module are disclosed....
6181500 Self servo rewrite method and apparatus  
A method and apparatus is disclosed that detects servo sectors that contain defects that need to be rewritten and writes in the servo field to correct the detected defects. The system includes a...
6181498 Recording and reproducing apparatus, information signal recording and reproducing system and method of managing invalid area information  
If a BS (bad spot) occurs when data is written, then BST (bad spot table) is updated and registered in an EOD (end of data), thereby making it possible to carry out a recovery operation with ease...
6178054 Selecting write fault thresholds by head and disc location in a disc drive  
A method is disclosed for optimizing write performance of a disc drive through the selection of optimum write thresholds. The disc drive has a controllably positionable head adjacent tracks defined...
6178053 Storage apparatus for reducing a read error caused by a thermal asperity of a magneto-resistive head  
For a read demodulating unit for demodulating read data and servo data which is used for head positioning from a reproduction waveform signal of a magneto-resistive head, a thermal asperity fault...
6175459 Magnetic disk drive with a disk medium defect detector and read channel IC used in the drive  
A magnetic disk drive capable of specifying even the type of a medium defect with a small number of read/write operations is disclosed. A read signal is sampled. A defect detector 40 of a read...
6175458 Control of servo timing mark detection windows  
A disk drive processing system controls a Servo Timing Mark (STM) detection window in disk drive during a head switch operation. In response to the head switch operation, the system disables a...
6172832 Data storage system with improved biasing techniques for magneto-resistive element  
A magnetic storage system capable of separating thermal signals from data signals is disclosed. The magnetic storage system includes a magnetic media and a head associated with the magnetic media....
6172829 Digital audio tape recording/reproducing apparatus for use with multiple formats  
A data recording and reproducing apparatus for recording and reproducing data on azimuth tracks of a magnetic tape in which the data may be audio data or computer data in any of several different...
6172828 Signal processing apparatus and a disk control apparatus, with head positioning control based on digitized servo data  
A signal processing device having a feature of analog-to-digital converting a burst signal has a feature of selecting a data bus to notify a disk control device of a conversion result via an NRZ...