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6421194 Disk drive head-select verification  
A method of storing data on a surface of a storage disk, the data being capable of verifying an identity of the surface, includes determining first check data from first alignment correction data...
6414809 Data storage device servo control apparatus and method  
A storage device with a disk-shaped recording medium having servo areas in which servo sectors are recorded and data areas in which data sectors are recorded; a read/write head to read and write...
6414811 Method for optimizing the read bias current of a magneto resistive head  
A method for setting a read bias current required for reading data written to a hard disk at an optimal bias current using a magneto-resistive (MR) head. The method for setting a read bias current...
6414807 Method and apparatus for optically sensing accurate clock patterns  
A disk drive system is described for forming and reading precise optically detectable patterns on rotating members of a disk and spindle assembly used in data storage system. In particular the...
6412058 Adaptive head address re-map for data storage devices  
A system, method, and article of manufacture for adaptive re-mapping of head addresses in a data storage device. A logical address received by the data storage device is converted into a...
6412083 Disk drive that supports a list-requesting command for enabling a host computer to assist in rescuing a rescue-candidate location having a drive-unrecoverable data  
There is disclosed a method of operating a disk drive for enabling a host computer to assist in rescuing a rescue-candidate location having drive-unrecoverable data. The method includes...
6404573 Full and half-rate signal space detection for channels with a time-varying MTR  
A detector is provided to detect data values within a data signal that is sampled to provide temporally separated data samples. A first detector portion is configured to determine the location of...
6404577 Trellis encoding and decoding of track identification indicia  
A method and apparatus for identifying a track (42) of a rotating disk (12) of a mass data storage device (10) uses EPR4 data detection techniques. The values of the encoded track identification...
6404570 Disk drive with adaptive channel optimization  
Adaptive channel optimization in a disk drive is achieved by selecting a track of the recording medium and then writing a first data pattern to opposite sides of the selected track. The first data...
6396651 Gear-shifting compensation system and method for nonlinear input elements  
The present invention comprises devices and methods for recovering a block of data. In a preferred embodiment, a block erroneously read due to improper read head nonlinearity compensation is...
6392831 Identification of defective servo information elements in a disc drive system  
A method and disc drive system identify defective servo information elements on a disc. Servo information elements are read from the track on the disc to receive first servo data status values...
6392829 Alternate randomizing for even/odd data tracks  
The present invention provides a method and storage device for reducing the occurrence of data miscompare errors. The method includes identifying a destination track as either an even track or an...
6385744 Data recording medium, data recording method and data reproducing method  
This invention is to record data and skip an ECC block containing a defective sector when the defective sector is detected in an optical disk in which data is recorded in an ECC block unit...
6384999 Rewrite with embedded reassign for data recovery from marginally defective data sites on a data storage device  
A method for recovering data from marginally defective data sites on a disk drive surface. If a user data site is determined to be marginally defective during a read operation, a read error...
6381082 Arrangement for reading information form a record carrier  
An arrangement for reading information from a record carrier, such as in a HDD, include a read head (Rmr1), an amplifier (74) for amplifying the signal read by the read head, an equalizer (76) for...
6381706 Fine granularity rewrite method and apparatus for data storage device  
A method for rewriting track packets that fail a check-after-write test onto a track of a storage medium is presented. Local packet address information is included in the track packet itself to...
6378107 Digital signal reproducing apparatus  
This invention relates to a digital signal reproducing apparatus. This invention is applicable to an apparatus such as a video tape recorder and an optical disk drive, using a Viterbi decoder...
6377417 Method for controlling repeatable runout compensation algorithm  
In a method for controlling a repeatable runout (RRO) compensation algorithm in a hard disk drive, it is determined whether to enable or disable an RRO compensation algorithm in a corresponding...
6373648 Disk head assembly with multiple read and/or write transducers for improved performance  
A recording disk apparatus is provided. The recording disk apparatus includes a recording disk having at least one recording surface with a plurality of spaced recording tracks. The recording disk...
6359744 Reducing thermal decay of data signals recorded on magnetic media  
A data storage device 15 comprises a recording head 35 and a recording media comprising a layer of magnetic material having an anisotropy that is substantially perpendicular to a plane of the...
6345074 Maximum likelihood servo detector for detecting an error correcting servo code recorded on a disc storage medium  
A disc storage system servo code detector is disclosed that provides enhanced error correction capabilities during both tracking and seeking by increasing a minimum distance dmin between valid...
6342986 Servo writing with simultaneous biasing of magneto-resistive read elements  
Apparatus and method for servo writing with simultaneous biasing of multiple magneto-resistive read elements in a disc drive head/disc assembly. A preamplifier circuit sequentially applies read...
6341045 Disk-shaped recording medium and formatting method thereof wherein historic information including a storage capacity of the disk-shaped recording medium is recorded thereon  
In a large-capacity FD comprising a disk-shaped recording medium on which a plurality of tracks are arranged with concentric circles, each track is divided into a predetermined number of sectors...
6337777 Method and apparatus for controlling data write operations  
A system for preventing off track data write operations in data storage devices such as hard disk drives. In a preferred embodiment, the amplitude of a head output signal is monitored. The output...
6336202 Data storage system, storage medium and method of controlling a data storage system  
A data storage system, a storage medium and a method of controlling a data storage system are described, which allow defects on a storage medium to be handled with a memory region of a reduced...
6335840 Thermal asperity pointer for servo sector  
A direct access storage device (DASD) servo control system controls movement of a magneto-resistive (MR) read/write head in response to a readback signal generated when the MR head repeatedly...
6335842 Magnetic recording apparatus with a head error detection circuit  
The present invention provides a magnetic recording apparatus for recording/reproducing a data with a comparatively high density. The magnetic recording apparatus comprises: a magnetic recording...
6327106 Disk drive having data-guarding firmware  
A disk drive includes a disk defining a multiplicity of sectors. A method of operating the disk drive includes a step of providing a firmware-controlled state machine which can be in any of a...
6320710 Tape reproduction apparatus and method  
The present invention enables to preferably correct mark patterns reproduced in parallel from a magnetic tape. A mark detection block 204 successively identifies as one of the plurality mark...
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...
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...
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...
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...