Abstract: The present invention provides a storage device and a writing unit diagnosing method, which can determine a defect in a writing unit at an early stage. There is provided a storage device, which includes writing units that write data to a storage medium, current application units that apply a current to the writing units, electric property measurement units that measure the electric property of the writing units at the time of applying a current by the current application units, and obtain electric property measured values, a storage unit that stores the electric property measured values obtained by the electric property measurement units, and a judgment unit that judges whether or not the writing units are abnormal based on the electric property measured values stored in the storage unit.

Abstract: Various embodiments of the present invention provide systems and methods for controlling access to a magnetic storage medium. As one example, a method for controlling access to a storage medium is disclosed that includes calculating a point to point error amount, and generating a incremental error value based at least in part on the point to point error amount. The incremental error value is applied incrementally across a defined number of clock cycles.

Abstract: Disclosed is a technique for updating a read-detect channel. A signal is processed in a read-detect channel that has one or more programmable registers. While signals continue to be processed by the read-detect channel, it is determined with a channel auxiliary processor whether to dynamically replace values of the one or more programmable registers. When it is determined that values of the one or more programmable registers are to be replaced, a channel auxiliary processor determines values for the one or more programmable registers and replaces existing values for the one or more programmable registers with the determined values.

Abstract: A method of determining a head characteristic, i.e. determining whether a head has a write characteristic stronger or weaker than that of a normal write head, and a recording medium suitable to perform the method. The method includes detecting a first error rate by writing data and then reading the written data without control pole tip protrusion (PTP) contralto compensate for thermal pole tip protrusion (TPTP) in a state where the head is fully cooled, detecting a second error rate by writing data and then reading the written data with the PTP control in the state where the head is fully cooled, calculating a difference between the first error rate and the second error rate, and determining based on the calculated error rate difference whether the head is a strong write head having a stronger write characteristic than that of the normal write head or a weak write head having a weaker write characteristic than that of the normal write head.

Abstract: Embodiments of the present invention efficiently conduct a test for detecting defects on a magnetic disk more accurately. According to one embodiment, a HDD carries out defect inspection of a magnetic disk using thermal fly height control (TFC). Changing a clearance by the TFC achieves defect inspection tests under varied test conditions without much decrease of throughput in manufacturing HDDs. First, a self analysis test (SAT) is carried out in a state that a heater power of P2 is supplied to a heater. Then, another SAT is carried out in a state that a heater power of P1 is supplied to the heater. The heater power P2 is larger than the heater power P1.

Abstract: A media storage device reads and writes data from and to a storage medium using a head and prevents in advance data loss due to thermal relaxation of data recorded on the storage medium. Table stores information which is related to a read error detected by a channel circuit in record units. The channel circuit measures information which is related to a read error and updates the information in the table. Further, data degradation is judged by this information which is related to the read error. Degradation of recorded data due to thermal relaxation can be detected accurately, and data loss can be prevented.

Abstract: A magnetic recording layer is formed on a surface of a substrate in magnetic recording media to define magnetic recording regions. Magnetic missing portions are provided in the magnetic recording regions, information cannot be magnetically recorded in the magnetic missing portions. The present invention provides magnetic recording media that enables authentication.

Abstract: A hard disk drive that includes a disk that contains at least one signal and a head that is coupled to the disk. The disk drive also contains a circuit that includes a data sampler that-generates a plurality of data samples from the signal, a harmonic sensor coupled to the data sampler and a spectral power accumulator coupled to the harmonic sensor. The harmonic sensor accumulates the data samples. The circuit includes a window generator that determines a window length of the data samples accumulated by the harmonic sensor. The spectral power accumulator accumulates the windows of sample data accumulated by the harmonic sensor. The sample data accumulated by the spectral power accumulator can be accessed by a processor that performs a spectral analysis of the data.

Abstract: Embodiments of the present invention efficiently format long sectors, without decreasing the performance, in a magnetic disk drive in which servo sectors are radially formed at regular intervals, and make full use of the ECC performance that is enhanced by the long sectors. In one embodiment, a data format in each zone on a magnetic disk is completed by a plurality of tracks N (N is an integer, which is 2 or more). The storage capacity per track of the outermost radius zone Z#1 is 150 kB. In this zone, long sectors each having a length of 32 kB are formatted with the number of tracks per format N#1=3. The storage capacity per track of the innermost radius zone Z#m is 80 kB. In this zone, long sectors each having a length of 32 kB are formatted with the number of tracks per format N#m=2.

Abstract: A data read system comprising a read channel for processing a signal, and a diagnostic controller in communication with the read channel. The diagnostic controller is configured to measure at least one metric of the read channel during processing of a signal containing unknown data. The measured metric is then compared against a stored nominal metric and a warning is generated in response to a result of the comparison. In particular, the warning is generated only if the difference between the measured metric and the stored nominal metric exceeds a threshold.

Abstract: A tape drive system which includes the ability to reliably reproduce LPOS information even if both of the servo channels of the tape drive system could not detect the LPOS information due to defects. The system recognizes that an LPOS sequence is sequentially incremented by one if a tape is moving in a forward direction and decremented by one if the tape is moving in a backward direction. This sequential property of the LPOS information lends itself to LPOS prediction, where the LPOS prediction is the previous LPOS value plus one if the tape is moving forward and the previous LPOS value minus one if the tape is moving backward. Even if the LPOS words from the two servo channels are both bad, but not all of the bits in the LPOS word are bad. The system uses the remaining good bits from the two servo channels to verify all of the bits of the LPOS prediction word.

Abstract: A hard disk drive with a disk that has a plurality of data bits. The drive includes a circuit that reads each data bit n times and selects a value for the bit based on the most frequent occurrence of one of a plurality of values. This process provides a voting technique that enhances the quality of accurately captured data.

Abstract: A determining unit determines whether a clock signal is oscillated with an oscillation amplitude equal to or greater than a predetermined value. An output control unit outputs the clock signal to an output destination when the determining unit determines that the clock signal is oscillated with the oscillation amplitude equal to or greater than the predetermined value.

Abstract: A disk drive has multiple disk surfaces and corresponding heads, each disk surface includes multiple regions, and each head is for recording on and playback of information from a corresponding disk surface. The data track density in a first region on a first disk surface is different than the data track density in a second region on a second disk surface, and the first and second regions are radially similarly situated regions. A method of sequentially accessing data in the first and second regions includes sequentially accessing data tracks in the first region and then sequentially accessing data tracks in the second region.

Abstract: Embodiments of the invention provide a magnetic disk drive capable of reducing an area used for a preamble of each data sector to increase the storage capacity. The magnetic disk drive adopts a data-surface servo system. In one embodiment, main preambles are written on a magnetic disk at a frequency of a data clock. Each of data sectors is written with a write clock that is synchronized with a signal obtained by reading the main preamble. The data sectors include sub preambles respectively. When the data sector which has been written in this manner is read, a read clock is synchronized by use of a signal obtained by reading the main preamble, and a signal obtained by reading the sub preamble included in a data sector to be read. The bit length of the sub preamble is shorter than that of the conventional preamble that is used to independently achieve the synchronization.

Abstract: Embodiments of the present invention provide a defect registration method for performing defect registration of sectors on a magnetic disk. In one embodiment, a rectangular detection window is applied to each defect sector. A threshold value of the detection window is set at 2. In addition, an additional sector group is defined for the detection window. The additional sector group is a target of the defect registration if the number of defect sectors exceeds the threshold value. The additional sector group covers sectors that are not judged as defects in defect detection inspection, but that are expected to be potentially defective. Even if the detection window is applied to a defect sector, an additional sector group is not generated. However, if the detection window is applied to a defect sector, an additional sector group is generated. If the detection window is applied to a defect pattern, an additional sector group is generated.

Abstract: In a perpendicular magnetic recording system, the data that is being written by the write channel is fed back into the read channel. The read channel processes the data and decides if the written sequence is likely to have very poor DC characteristics. If that is the case, the write channel changes a scrambler seed and rewrites the data using the new scrambler seed. The data may also be inspected for patterns that might cause large baseline wander before being written to disk, i.e., in the write channel. A data sequence may be repeatedly scrambled and encoded until an acceptable level of estimated DC-wander has been achieved. The data sequence may then be written to disk.

Abstract: A recording system, such as a magnetic or optical recording system, employs optimization metrics that are independent of a target partial response for equalization of a signal read from a recording channel. The optimization metrics employ samples adjacent to codeword boundaries of codewords representing encoded data, such as servo data, read from a recording medium. The optimization metrics are used to select filter parameters and/or tap weights for equalization. The filter parameters and/or tap weights might be derived based on the type of data read from the recording medium, the type of detector employed to detect the codewords of the read data, and the type of encoder/decoder employed for the read data.

Abstract: Data reliability testing for a magnetic tape drive is conducted separately for the channels of a magnetic tape drive which write and read tracks of a multiple track magnetic tape. Memory stores testing data representing data separately written to tracks of a multiple track magnetic tape; each of a plurality of read channels reads data sensed by a tape head from a separate track of a magnetic tape; and error processing logic detects differences between data from each of a plurality of the read channels, and stored testing data of the memory representing data written to the same separate tracks.

Abstract: Embodiments of the invention provide a servo information write method that makes it possible to properly locate the last-written servo information even when old servo information is overwritten by new servo information. In one embodiment, a servo track writer controller, which is within a servo track writer, reads a serial number (S/N) from a HDD (step 101), and acquires a magnetic disk drive servo information write count (P-ID) from a manufacturing process host (step 102). The next step (step 103) is then performed to control a positioner and a read/write channel so as to start writing servo information onto a magnetic disk. Servo information is sequentially written until the last track is written into (step 104). When the Nth servo information is to be written, a P-ID (N) is written subsequently to a burst signal (step 105). When the last track is written into in step 104, step 106 is performed to notify the manufacturing process host that the Nth servo information write is performed.

Abstract: There are provided a cache region that stores write data from a host device, storage media, a data storage region for the storage media, and a comparison unit. A first comparison object is generated for N items of write data on the cache region and the N items of write data are transferred to the data storage region. Write data is read from a designated address of the data storage region and this write data is written to the storage media. When N items of write data have been read, a second comparison object is generated in respect of the write data. The comparison unit compares the first comparison object and the second comparison object, and if the result of the comparison is a mismatch, the N items of write data on the cache region are again transferred to the data storage region.

Abstract: A method for identifying adjacent track interference for a head is provided. The method comprises writing a first data track at a predetermined track position; writing a second data track two track positions away from the first data track; and validating the position of the first data track and the second data track. Upon validation the method further comprises writing a third data track between the first data track and the second data track and analyzing a signal profile of at least one of the first data track and the second data track for adjacent track interference.

Abstract: A method and system for secure data storage and retrieval is provided. A sequence of data units is divided into multiple subsets of data units corresponding to multiple data channels. The multiple data channels are assigned to multiple data writers based on a key code. Then, each subset of data units is transferred to a writer via an assigned channel for writing to storage media. Thereafter, to securely retrieve the stored data, each subset of data units is read from the storage media using a data reader. The original sequence of data units can only be reassembled using the key code for properly reassembling the subsets of data units into their original sequence.

Abstract: Embodiments of the present invention provide optimization of read/write channels in a recording system by embedding channel optimization algorithm/procedure into the channels, or a system-on-chip (SOC) where a read/write channel is integrated with a disk drive controller, according to an Embedded Channel Optimization Solution (ECOS).

Abstract: A user interface in a file-based networked storage server enables a user to selectively enable or disable an option to require read-after-write verification for sets of data stored by the file-based networked storage server. In response to a request from a client, specified data is written to a magnetic storage device managed by the file-based networked storage server. A determination is made of whether the specified data is associated with a set of data for which the option to require read-after-write verification is enabled, and if so, then the specified data written to the magnetic storage device is verified, prior to, and as a precondition of, acknowledging completion of the write to the client. The specified data written to the magnetic storage device is designated as being in a WORM state only after successful completion of said writing and said verifying.

Abstract: Methods and apparatus are disclosed for writing and verifying servo frames written on a storage medium, for verifying data areas of a storage medium, and for writing and verifying servo frames and data areas of a storage medium. In one example, the writing of at least a portion of a position field of a servo frame to a track of the storage medium is interleaved with reading of at least a portion of a previously written logic field of a servo frame of a track of the storage medium whereby said portion of the previously written logic field can be verified during the servo writing process.

Abstract: Methods and apparatus for decoding codewords using message passing decoding techniques which are particularly well suited for use with low density parity check (LDPC) codes and long codewords are described. The described methods allow decoding graph structures which are largely comprised of multiple identical copies of a much smaller graph. Copies of the smaller graph are subject to a controlled permutation operation to create the larger graph structure. The same controlled permutations are directly implemented to support message passing between the replicated copies of the small graph. Messages corresponding to individual copies of the graph are stored in a memory and accessed in sets, one from each copy of the graph, using a SIMD read or write instruction. The graph permutation operation may be implemented by simply reordering messages, e.g.

Abstract: The disclosure describes a data storage system that includes a signal defect correction system for removing signal defects in magnetoresistive head playback signals. The signal defect correction system utilizes a matched finite impulse response (FIR) filter and digital signal processing algorithms. The matched FIR filter is designed with an impulse response that is the time reversed, complex conjugate of a signal defect model. The signal defect model is generated from a number of sample playback signals. The matched FIR filter is applied to the playback signal and digital signal processing techniques are applied to the filter response to detect a signal defect in the playback signal and estimate the amplitude and location of the signal defect. The signal defect model is retrieved from memory and applied to the playback signal using the amplitude and location estimates to substantially remove the signal defect from the playback signal.

Abstract: A media event timer includes a counter module for generating a sequence of counts based on a clock signal of a disk drive unit. A counter reset module sets the counter module to a reset count in response to a servo address mark detection signal. A detector module detects that a servo address mark has been missed and sets the counter module to a restart count when the servo address mark has been missed. A trigger module triggers a first media event when a first media event count compares favorably to a count of the sequence of counts.

Abstract: A programmable activate-precharge cycle are provided for a DRAM device. Activate and precharge signals associated with the activate-precharge cycle are generated on the basis of the programmed rate and precharge time with respect to an internal clock of the DRAM device. The activate and precharge signals are coupled to wordlines of the DRAM device, and switched from one wordline to another under internal or external control. One or more functions of the DRAM device are tested while the activate and precharge signals are coupled to wordline. The manner in which switching the activate and precharge signals from one wordline to another wordline is configured depending on the type of testing to be conducted.

Abstract: Disclosed are a method and system for distinguishing spatial and thermal defects on perpendicular media. The magnetic domains of the perpendicular media are oriented to have a first polarity, scanned using a read head, oriented to have a second polarity and scanned again. The signals from the read head are combined to produce output signals having improved signal to noise ratios from which the locations of spatial and thermal defects can be identified and distinguished.

Abstract: Spinstand test improvement that measures Functional Byte Error Rate (F-BER) of a disk. The F-BER is correlated to the BER of a disk. The F-BER test is faster than a BER test. The F-BER test is incorporated into a spinstand tester or the software associated with a spinstand tester.

Abstract: Embodiments in accordance with the present invention relate to improving error recovery process performance. A head slider in an embodiment of this invention includes a heater for adjusting a clearance between a head element section and a magnetic disk. During an error recovery process (ERP) for a reading error, if a particular environmental temperature is in a low-temperature region, a microprocessing unit (MPU) executes the ERP steps of increasing a heater power value of the heater (i.e., STEP X to STEP X+2), preferentially over the ERP steps of reducing the heater power (i.e., STEP X+3 to STEP X+5). In the low-temperature region, the possibility of error recovery in an earlier step can be raised by executing the heater power increasing ERP steps earlier than the heater power reducing ERP steps.

Abstract: A determining unit retrieves status information relating to recording or reproducing data on the magnetic disk, and determines whether to re-record data recorded in a recording area on the magnetic disk based on the retrieved status information. When the determining unit determines to re-record first data recorded in a first recording area, a re-recording unit re-records at least one of the first data and second data recorded in a second recording area near the first recording area on the magnetic disk.

Abstract: A memory controller couples 32-bit data words to and from a DRAM. The DRAM generates error checking and correcting syndromes to check and correct read data. The DRAM generates the syndromes from respective 128-bit data words each formed by 4 32-bit data words written to the DRAM, and thereby achieves a low syndrome bit overhead. The memory controller may write data words to the DRAM having less than 128 bits by first reading 4 32-bit words from the DRAM, substituting the write data for a corresponding number of bits of read data, and writing the new 128-bit word to the DRAM by writing 4 32-bit words.

Abstract: A random access memory (RAM) in a programmable logic device (PLD) supports error correction as well as a configurable data width. The number of bits in a user data word varies by the selected configuration of the RAM, while the number of bits in the error correction code (ECC) is unvarying, and is based on the total width of the memory. In some embodiments, separate ports are provided for the user data and the ECC data. Thus, ECC data can be written to an ECC portion of the RAM array at a given RAM address, while at the same time user data is written to or read from a configurable user data portion of the RAM array at the same RAM address. In other embodiments, a single memory access port is used for both user data and ECC data.

Abstract: A medium storage device writes or read data on a storage medium synchronizing the rotation of the storage medium with the DSW method for decreasing the gap length considering the rotation jitter. The medium storage device has a controller for generating synchronization timing signals during reading/writing from a clock, and a processing unit for calculating the correction value of the frequency from the measurement result of the servo synchronization mark space of the storage medium. The processing unit judges whether the servo synchronization mark has been correctly detected and calculates the frequency correction value. Therefore changing the synchronization timing using the SSM interval detected in error can be prevented, and the danger of data corruption can be avoided.

Abstract: 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 each of a plurality of fixed offsets from a center of the selected track. The main controller samples a gain in the read channel a plurality of times while the head is reading the data block at each of the plurality of fixed offsets to obtain a plurality of gain samples for each of the plurality of fixed offsets. If the data block was written off-track with a non-constant offset, the main controller determines an approximate starting position and an approximate rate of change of an off-track deviation of the data block based on the plurality of gain samples for the plurality of fixed offsets.

Abstract: A memory device includes at least two DRAM memory modules, at least one external ECC module, and a memory controller. The external ECC module provides the memory modules with ECC functionality. Each memory module is connected to the memory controller via a respective memory channel. The external ECC modules are connected to the memory controller via a common ECC channel. Each external ECC module is assigned to a group of the memory modules. The memory modules of one group with respective ECC modules are synchronously operated by the memory controller.

Abstract: An apparatus for error-correction encoding information includes, in one embodiment, an outer encode that generates algebraically decodable data, the outer encoder operatively coupled to one or more inner encoders that generate iteratively decodable data. The outer encoder is adapted to encode a group of (q?r) original data symbols using r code symbols to produce q outer-encoded symbols, wherein the coding gain of the outer encoder provides for the correction of up to x symbol errors and (r?2x) symbol erasures where r is an integer greater than zero and x is an integer such that 0 ? x < r 2 . The one or more iterative EC-inner encoders are adapted to inner encode each of the q outer-encoded symbols or combinations of several outer-encoded symbols independently of the others, wherein each symbol is encoded with h additional code bits.

Abstract: A method of determining errors in a data storage device is disclosed. The disclosed method includes receiving a first code word from the data storage device. The method further includes determining whether a data error exists in the code word by analyzing a plurality of subsequent code words. Detecting a data error includes calculating first, second, and third checksums for each of a plurality of subsequent code words and determining whether there is an insertion or deletion error based on the calculated checksums. A further method includes receiving location information of errors on a data medium and adjusting a write clock frequency to reduce the probability of creating errors on the data medium during a write process.

Abstract: A disk drive clock circuit includes a servo clock generator and a disk locked frequency converter. The servo clock generator generates a servo clock signal in response to servo information read from a data storage disk in a disk drive. The disk locked frequency converter responds to the servo clock signal by generating a modified clock signal having a different frequency, and adjusts timing of an edge of the modified clock signal in response to a timing event identified from the servo information read from the disk. The disk locked frequency converter can include a divide-by-n counter that is configured to divide the frequency of the servo clock signal by a number n to generate the modified clock signal. The disk locked frequency converter can reset the divide-by-n counter to a defined value in response to the timing event. The modified clock signal can thereby be phase locked to the servo information on the disk.

Abstract: Data tracks are written across a width of a tape by positioning a first head section across the tape and writing a first subset of data tracks onto the tape with a first plurality of write elements on the first head section. A second head section is positioned across the tape separately from the first head. A second subset of data tracks is written onto the tape with a second plurality of write elements on the second head section so that the second subset is interleaved with the first subset. A third head section is positioned across the tape separately from the first head and the second head. The first subset and second subsets are read with a plurality of read elements on the third head section to verify that data was correctly written onto the tape.

Abstract: A recording system, such as a magnetic or optical recording system, employs an address mark (AM) detector that searches for an address mark pattern that is augmented by one or more bits of a preamble field so that a false detection rate is reduced. In one case, the address mark includes L bits, and the AM detector compares i) the input detected bits with ii) a SAM pattern of L bits augmented with m bits of the preamble to detect the SAM. In another case, the address mark includes less than L bits (e.g., L?k bits), and the AM detector compares i) the input detected bits with ii) a SAM bit-pattern of (L?k) bits augmented with m bits of the preamble to detect the SAM.

Abstract: A clock tracking circuit and method uses a clock compensation signal to compensate for timing marks on a media disk. The clock compensation signal may compensate for at least one of improper clock track closure and written-in jitter of the timing marks used to produce the measured clock signal. The clock compensation signal may be used to control a controllable oscillator used to generate the clock signal that thereby provides a compensated clock signal.

Abstract: A method for generating an anti-shrink to delta creep amplitude performance metric for a tensilized tape. The method may include the steps of determining a zero point of the tensilized tape, determining a total length of the tensilized tape, generating a zero point ratio by dividing the zero point of the tensilized tape by the total length of the tensilized tape, and generating the anti-shrink to delta creep amplitude performance metric by subtracting the zero point ratio from a constant.

Abstract: Various embodiments of the present invention provide systems and methods for synchronizing data processing. As one example, a method for synchronizing data processing is disclosed that includes receiving a data input, and sampling the data input at a sample period to generate a sample set. A first pattern is received and a first periodic boundary associated with the first pattern is identified. In one particular case, the first pattern is a preamble pattern included as sector data on a storage medium, and the first periodic boundary is a 4T boundary. Further, a second pattern is detected in the sample that is used to establish a second periodic boundary. In one particular case, the second pattern is a SAM pattern included as sector data on a storage medium, and the second periodic boundary is a 1T boundary. Based at least in part on the first periodic boundary and the second periodic boundary, a time to transmit or assert a data-found signal is determined.

Abstract: A method for testing the integrity of a memory with defective sections under a plurality of operating environments includes testing the memory with defective sections under a plurality of operating environments, recording results of each operating environment test, and comparing the results of the tests. If the results of are the same, the memory with defective sections is declared to have integrity. If not, the memory with defective sections is declared to not have integrity.

Abstract: An apparatus, system, and method are disclosed for variable data density patterned media. The apparatus includes a patterned media recording surface comprising a plurality of sectors. Each sector may include a synchronization region configured to generate a signal in a read head, a first data region with a first data density configured to generate a signal with a first frequency, and at least a second data region with a second data density configured to generate a signal with a second frequency. The system includes a hard disk drive and the apparatus. The method includes sensing a signal in a read head, synchronizing the frequency and phase of a write clock with a predetermined frequency and phase of a synchronization region, and modifying the frequency of the write clock after a period of time determined in response to at least one physical characteristic of the disk.

Abstract: A system and method for a servo controller (SC) used in an embedded disk controller for adjusting stored servo skew values based on measured skew values is provided. The system includes, a servo timing controller, wherein the servo timing controller includes a first register that stores measured servo skew values at a given time; a first set of registers that receive stored skew values and the measured skew values; and firmware that adjusts the skew values based on the measured skew values measured by a reference timer. The process includes, measuring actual skew values during a head change in a read operation; comparing the measured skew values with the stored skew values; adjusting the skew value based on the comparison; and adjusting a servo field timer based on the adjusted skew value.