Abstract: Write enhancement circuitry on the head carrier of a magnetic recording disk drive provides additional write current overshoot beyond that provided by the write driver circuitry. The write enhancement circuitry is formed on the head carrier as ladder network blocks. A first ladder network block is a first capacitor C1 located in parallel with the write coil. The second ladder network block includes a second capacitor C2 having substantially the same inductance L2. The compensation circuitry is referred to as a ladder network because additional ladder blocks, like the second block but with different values of capacitance and inductance, may be located on the head carrier.

Abstract: Various embodiments of the present invention provide apparatuses, systems and methods for magnetic recording with a multi-level write current waveform. For example, an apparatus for magnetic recording with a multi-level write current waveform is disclosed that includes a pattern detection circuit operable to detect patterns in data to be written by the magnetic write head and to yield a pattern indicator signal, and a write driver operable to generate the multi-level write current waveform for the magnetic write head. At least one electrical characteristic of the multi-level write current waveform is based upon the patterns detected by the pattern detection circuit.

Abstract: Preamble fields are written on a storage disk in a hard disk drive in a way that reduces track squeeze. Preamble fields for a particular data storage track on the storage disk are written over multiple revolutions of the storage disk to eliminate low-frequency variations of the preamble stitch line from an ideal position of the preamble stitch line.

Abstract: A magnetic tape media for storing data includes at least one servo band extending along the magnetic tape media and having servo information encoded by an M-ary alphabet A comprising M>2 different symbols and is arranged in a set of words. Each word of the set of words contains synchronization information, wherein each symbol used for representing the synchronization information is from a set B of m symbols, which set B is a proper subset of the symbols in the alphabet A such that 1?m?M; longitudinal position information, wherein each symbol used for representing the longitudinal position information is from a set C of M-m symbols, which set C is a complementary set to set B; and other information, wherein each symbol used for representing the other information is from the set C of M-m symbols.

Abstract: Interface circuitry of a storage device or other type of processing device comprises a digital input detector and an adaptive power supply. The digital input detector comprises an input transistor. The adaptive power supply provides a variable supply voltage to the digital input detector that varies with a threshold voltage of the input transistor. In one embodiment, the variable supply voltage provided to the digital input detector by the adaptive power supply varies with the threshold voltage of the input transistor about a set point value determined as a function of an expected logic level of an input signal. For example, the set point value may be determined as a function of a minimum expected logic high input signal level. In such an arrangement, the input transistor is biased at or close to the threshold voltage for an input signal having the minimum expected logic high input signal level.

Abstract: A servo write apparatus, comprising a first servo write head configured to only encode a single first magnetic dibit onto a magnetic information storage medium, wherein the first magnetic dibit comprises a first azimuthal slope. The servo write apparatus further comprises a second servo write head configured to encode one or more second magnetic dibits onto a magnetic information storage medium, wherein the second magnetic dibit comprises a second azimuthal slope, wherein the first azimuthal slope differs from the second azimuthal slope.

Abstract: A method for calibrating a reflection compensator is provided. A delay is initially set to a predetermined minimum, and an input pulse is transmitted across a transmission line. A compensation current is then applied after the delay. The reflection from the transmission line is digitized to generate a measurement, and a determination is made as to whether the compensation current substantially compensates for the reflection. If the compensation current does not substantially compensate for the reflection, then the delay is adjusted, and the process is repeated until the compensation current substantially compensates for the reflection.

Abstract: In one embodiment, a tape drive system includes a read channel configured for performing a portion of a data transfer operation, logic adapted for monitoring the data transfer operation for detecting one or more temps within a sliding window spanning a last group of datasets processed, logic adapted for measuring interference between first tier and second tier recovery methods based on the monitoring, logic adapted for setting a backhitch delay based on conditions relating to the interference of first tier and second tier recovery methods as it relates to a determined error burst, and logic adapted for performing a backhitch and altering at least one condition of the data transfer operation after the backhitch delay.

Abstract: Hardware-based methods and apparatus are provided for inter-track interference mitigation in magnetic recording systems. Inter-track interference (ITI) cancellation data is stored in a memory of a read channel of a magnetic recording system. The memory can be in a write data path or a read data path of the read channel. The inter-track interference cancellation data is optionally provided to an inter-track interference mitigation circuit using at least a portion of a write data path, for example, based on a control signal. The storage of the inter-track interference cancellation data can be in response to a second control signal.

Abstract: Hardware-based methods and apparatus are provided for inter-track interference mitigation in magnetic recording systems. Inter-track interference (ITI) is mitigated in a magnetic recording system by obtaining ITI cancellation data; and providing the ITI cancellation data to an ITI mitigation circuit using a write data path in the magnetic recording system. The write data path can optionally operate substantially simultaneously with the read data path performing the read operation. The ITI cancellation data comprises, for example, user data and/or media data.

Abstract: A hard disk drive or other disk-based storage device comprises a storage disk, a read/write head configured to read data from and write data to the storage disk, and control circuitry coupled to the read/write head and configured to process data received from and supplied to the read/write head and to control positioning of the read/write head relative to the storage disk. The control circuitry is further configured to adjust at least one parameter of a write signal for a target bit to be written to the storage disk based on respective magnetization polarities of one or more adjacent bits previously written to the storage disk.

Abstract: In one embodiment, a magnetic data storage system includes a bit patterned magnetic medium, wherein centers of bits in adjacent data tracks do not lie on a common line in a cross-track direction, a magnetic head having a writer element having a width greater than a width of a data track in a track width direction adapted for writing data successively to at least two adjacent data tracks of the magnetic medium, and a reader element having a width larger than the width of a data track in the track width direction adapted for reading data concurrently from the at least two adjacent data tracks of the magnetic medium in a single pass, a drive mechanism for passing the magnetic medium over the magnetic head, and a controller electrically coupled to the magnetic head for controlling operation of the magnetic head.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, some embodiments of the present invention provide clock generation systems that include: a first clock multiplier circuit, a second clock multiplier circuit, a modulus accumulator circuit, and a data clock phase control circuit. The first clock multiplier circuit is operable to multiply a reference clock by a first multiplier to yield a first domain clock, and the second clock multiplier circuit is operable to multiply the reference clock by a second multiplier to yield a second domain clock. The modulus accumulator circuit is operable to yield a value indicating a fractional amount of the second domain clock that an edge of the second domain clock is offset from a trigger signal. The data clock phase control circuit is operable to phase shift the second domain clock by a phase amount corresponding to the fractional amount.

Abstract: In one embodiment, a read channel comprises: a preprocessor for receiving a first signal and producing a second signal from the first signal using current values of a positive coefficient, a zero coefficient, and a negative coefficient; an interpolator for producing a third signal based on the second signal; and a slicer for producing a fourth signal from the third signal by estimating a level for the third signal. The fourth signal is at one of three levels consisting of a positive level, a zero level, and a negative level. For every n first signals received by the preprocessor, the current value of one of the positive coefficient, the zero coefficient, and the negative coefficient is adjusted depending on which of the three levels the fourth signal is at.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes a noise predictive filter circuit, a data detector circuit, and a first and a second pattern dependent adaptive target circuits. The noise predictive filter circuit includes at least a first pattern dependent filter circuit operable to perform noise predictive filtering on a data input for a first pattern using a first adaptive target to yield a first noise predictive output, and a second pattern dependent filter circuit operable to perform noise predictive filtering on the data input for a second pattern using a second adaptive target to yield a second noise predictive output. The data detector circuit is operable to apply a data detection algorithm to the first noise predictive output and the second noise predictive output to yield a detected output.

Abstract: Methods and apparatuses for contiguous data address management are provided. In one embodiment, an apparatus may comprise a processor configured to receive a write command including data to be written to a plurality of logical block addresses (LBAs); determine if the plurality of LBAs includes LBAs from a plurality of logical bands; and when the plurality of LBAs includes LBAs from a plurality of logical bands, combine the plurality of logical bands into a single logical band and write the data to the single logical band. In another embodiment, the processor may be further configured to separate the single logical band into the plurality of logical bands when the data written to the plurality of LBAs becomes invalid.

Abstract: Methods and apparatuses for managing read or write errors are disclosed. In one embodiment, a method may comprise receiving a command to perform an operation associated with first data and a first address of a data storage medium, performing the operation at the first address, retrying the operation when the operation did not complete successfully, and storing the first data to a second address when a first threshold is exceeded. In another embodiment, an apparatus may comprise a processor configured to: receive a command to perform an operation associated with first data and a first address of a data storage medium, perform the operation at the first address, retry the operation when the operation did not complete successfully, and store the first data to a second address when a first threshold is exceeded.

Abstract: In one embodiment, a method includes spiral writing a DC pattern onto a magnetic disk medium using a writer of a magnetic head while moving the magnetic head in a direction about parallel to a radial direction of the magnetic disk medium while rotating the magnetic disk medium, reading the magnetic disk medium while moving the magnetic head in the direction about parallel to the radial direction of the magnetic disk medium while rotating the magnetic disk medium, and calculating a track pitch interval between data tracks of the magnetic disk medium based on the reading of the magnetic disk medium. In another embodiment, a magnetic disk medium includes a DC spiral pattern in a radial region further outward and/or a radial region further inward than a radial region where data is recorded.

Abstract: A system and method of establishing write timing in a disk drive using bit patterned media and a magnetic head with read-write offset in which servoing and writing occur on different tracks with timing offsets. Initially, the distance between the servoing and writing tracks is determined for each track/head position in accordance with head geometry and skew angle. The relative timing errors are then measured by iteratively writing data at timing offset increments to determine the optimal timing offset for the servoing/writing track pair, and then writing the offset to sync fields on the servoing tracks of the disk.

Abstract: Methods and apparatuses for data sector cluster-based data recording are disclosed. In one embodiment, an apparatus may comprise a processor configured to receive a write request containing host data for writing to a target location of a data storage medium. A target location may comprise one or more clusters, where a cluster may be multiple sequentially-numbered data storage addresses of the data storage medium. The processor may write at least one cluster of the target location with host data and dummy data pursuant to the write request, dummy data being arbitrary data written to fill data storage addresses in the target location not written by host data.

Abstract: Described embodiments provide a method of cancelling inter-track interference (ITI) from one or more sectors read from a desired track of a storage medium. A read channel reads sectors in a desired track of the storage medium. A decoder of the read channel decodes the read sectors, and if the read sectors are incorrectly recovered from the storage medium, selected sectors of a first adjacent track and a second adjacent track are read. An ITI canceller of the read channel estimates ITI in the read sectors of the desired track corresponding to the selected sectors of each adjacent track and subtracts the estimated ITI of each adjacent track from the data for the sectors of the desired track, providing updated sector data. The ITI cancelled data is replayed to the decoder, which decodes the ITT cancelled data and provides the decoded ITI cancelled data as output of the read channel.

Abstract: Various embodiments of the present invention provide systems and methods for calculating and/or modifying fly height. For example, a circuit for calculating fly height is disclosed that includes: a first pattern detector circuit, a second pattern detector circuit, a first pattern fly height calculation circuit, a second pattern fly height calculation circuit, a first averaging circuit, a second averaging circuit, and a combining circuit.

Abstract: Embodiments described herein provide for patterned media concentric zones with an alternating series of concentric servo zones and overlap zones. The overlap zones facilitate the writing of servo data between servo zones of different servo frequency. The overlap zones may be dual frequency zones. The dual frequency zones have a first set of overlap patterns with the substantially identical pattern as the bordering lower frequency servo zone and a second set of overlap patterns with the substantially identical pattern as the bordering higher frequency servo zone. A bootstrap zone can be included near the inner diameter to assist initial servo writing. Alternatively the overlap zones are bootstrap zones. Such bootstrap zones have both bootstrap patterns and overlap patterns, the overlap patterns have the substantially identical pattern as a bordering servo zone. Bootstrap patterns only require DC magnetization for servo operability.

Abstract: Embodiments described herein provide for patterned media concentric zones with an alternating series of concentric servo zones and overlap zones. The overlap zones facilitate the writing of servo data between servo zones of different servo frequency. The overlap zones may be dual frequency zones. The dual frequency zones have a first set of overlap patterns with the substantially identical pattern as the bordering lower frequency servo zone and a second set of overlap patterns with the substantially identical pattern as the bordering higher frequency servo zone. A bootstrap zone can be included near the inner diameter to assist initial servo writing. Alternatively the overlap zones are bootstrap zones. Such bootstrap zones have both bootstrap patterns and overlap patterns, the overlap patterns have the substantially identical pattern as a bordering servo zone. Bootstrap patterns only require DC magnetization for servo operability.

Abstract: A storage system comprises a first storage device having a first plurality of hard disk drives and a first controller. The first controller stores data in the first plurality of hard disk drives by stripes. Each stripe includes M data and N parity data allocated to M+N hard disk drives of the first plurality of hard disk drives. A first hard disk drive includes data or parity data of both a first stripe of the stripes and a second stripe of the stripes, while a second hard disk drive includes data or parity data of only one of the first stripe or the second stripe. During data recovery involving failure of one of the first plurality of hard disk drives, the data in the failed hard disk drive is recovered for each stripe by calculation using data and parity data in other hard disk drives for each stripe.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is discussed that includes: a servo address mark count circuit, a user sync mark count circuit, and an offset calculation circuit. The servo address mark count circuit is operable to provide: a first count corresponding to a first servo address mark within a first track of a storage medium, a second count corresponding to a second servo address mark within the first track, a third count corresponding to a third servo address mark within a second track of the storage medium, and a fourth count corresponding to a fourth servo address mark within the second track. The user sync mark count circuit is operable to provide: a fifth count corresponding to a first user sync mark within the first track, and to provide a sixth count corresponding to a second user sync mark within the second track.

Abstract: A given reference pattern is written on bit patterned media that has an initial reference pattern already disposed thereon. A write phase and frequency is detected based on the initial reference pattern and the given reference pattern is written on the bit patterned media at the detected write phase and frequency.

Abstract: A method for longitudinal position (LPOS) detection in a magnetic tape storage system for storing data upon linear tape open (LTO) magnetic storage tape, which data includes odd and even 36-bit LPOS words with error correcting ability. The method includes first encoding positional information onto the tape within the 36-bit LPOS words using each LPOS word's 8-bit sync mark field, and six of each LPOS word's 4-bit symbol fields, wherein 6 of 24 total bits comprise the encoded 8-bit sync mark field: Sy, and six 4-bit symbol fields are utilized as parity bits. The magnetic tape storage system passes the LTO magnetic storage tape encoded with the odd and even LPOS words with error correcting ability longitudinally across a servo reader/writer at a known speed, decoding the encoded positional information and detecting and correcting both ambiguous bits and single erroneous bit errors.

Abstract: A method for randomizing data to mitigate false VFO detection is described. In one embodiment, such a method includes simultaneously receiving multiple input data streams. Each input data stream is associated with a different track on a magnetic tape medium. The input data streams are simultaneously scrambled to produce multiple randomized data streams. The input data streams are scrambled such that different bit patterns are produced in the randomized data streams even where corresponding bit patterns in the input data streams are identical. The randomized data streams are simultaneously written to their associated data tracks on the magnetic tape medium. A corresponding apparatus is also described.

Abstract: Techniques for processing tape storage include determining a current position of a read device to read a data block from a tape storage medium having a plurality of duplicate data areas, receiving a request to read a data block from the tape storage medium, and reading the requested data block from a duplicate data area from among the plurality of duplicate data areas that is nearest the current position of the read device.

Abstract: Various embodiments of the present invention provide systems and methods for format efficient data storage. As an example, a data storage device is described that includes: a storage medium, a read/write head assembly, and a read channel circuit. The read/write head assembly is disposed in relation to the storage medium and operable to sense information corresponding to an encoded codeword. The read channel circuit is operable to receive the encoded codeword. The read channel circuit includes a missing symbols insertion circuit, a codeword de-scramble circuit, an address insertion circuit, and a data decoder circuit. The missing symbols insertion circuit, the codeword de-scramble circuit, and the address insertion circuit together are operable to pad a derivative of the encoded codeword with a plurality of symbols, to de-scramble the derivative of the encoded codeword, and to insert address information corresponding to the derivative of the encoded codeword to yield a modified encoded codeword.

Abstract: Provided are a computer program product, system, and method for a magnetic disk drive. The disk drive has at least one disk platter having at least one recordable disk surface having an areal density of at least 200 gigabits per square inch. Either a diameter of the at least one disk platter is greater than 3.5 inches or the at least one disk platter rotates at less than 5400 RPMs. A read/write head reads and writes tracks of data with respect to the at least one disk surface. Modified tracks from write requests to write to the at least one disk surface on the at least one disk platter are cached in a non-volatile storage device for caching modified tracks. Modified tracks are cached in the non-volatile storage device to later destage to the at least one disk surface.

Abstract: According to one embodiment, a position demodulator includes a demodulator, a phase corrector, and a position demodulating module. The demodulator demodulates a first demodulated signal and a second demodulated signal having a phase difference of 90 degrees from the first demodulated signal as a result of discrete Fourier transform operation on a read signal of a null servo pattern recorded in a servo area of a medium read out by a head. The phase corrector carries out correction to tilt respective vectors of the first demodulated signal and the second demodulated signal represented on a phase plane by a predetermined angle. The position demodulating module demodulates a positional signal for determining the position of the core of the head based on the first demodulated signal and the second demodulated signal corrected by the phase corrector.

Abstract: A head assembly according to one embodiment includes at least one module having magnetic transducers for reading and/or writing to a magnetic tape; electronics electrically coupled to the transducers, the electronics comprising at least one of amplifiers; bias circuitry; write drivers; write resistors; a memory device; and a chip with at least one of identification information about the head assembly, customization data, and firmware; and a connector for detachably interfacing to a drive having a head region for receiving the head assembly. A magnetic tape drive according to one embodiment includes a head region for removably receiving a head assembly; a mechanical interface to facilitate alignment of the head assembly when inserted in the head region; and a connector for detachably interfacing with the head assembly. Additional systems and methods are also presented.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes a codeword detector circuit operable to apply a codeword based data detection algorithm to a data input corresponding to an encoded servo data region to yield a detected output, and a servo address mark processing circuit operable to identify a pre-defined pattern in the detected output.

Abstract: A printed circuit cable assembly (PCCA) for a hard disk drive (HDD) is disclosed. The PCCA includes a stiffener portion having an elongated shape that includes an integrated circuit (IC) chip. The PCCA also includes a flexible portion extending from the elongated stiffener portion, wherein the PCCA is configured to be mountable on a headstack of the HDD such that an entire footprint of the IC chip overlays a metallic portion of the headstack of the HDD.

Abstract: A method and system for tracking a sequence of bad blocks in a RAID system by storing the logical block address of the first bad block and the number of bad blocks in the sequence is disclosed. The method and system may also track multiple sequences of bad blocks by storing a memory pointer to the next sequence in each previous sequence in an expandable linked list configuration.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes: a data detector circuit, a data decoder circuit, and a multi-path circuit. The data detector circuit is operable to apply a data detection algorithm to a data input and a decoder output to yield a detected output. The data decoder circuit is operable to apply a decoding algorithm to a decoder input to yield the decoder output and a status input. The multi-path circuit is operable to provide the decoder input based at least in part on the detected output and the status input.

Abstract: For determining an access sequence of a plurality of data groups stored on a tape medium, a first data group in the access sequence is selected based on which data group in the plurality of data groups has a beginning closest to a current position of the tape medium. A second data group in the access sequence is selected based on which remaining data group in the plurality of data groups has a beginning closest to an end of the first data group in the access sequence.

Abstract: An apparatus and associated method is presently disclosed for a control circuitry capable of managing a heat source used in data storage applications. Various embodiments of the present invention are generally directed to a heat source directed at a data storage medium with a synchronization signal and a serial interface that are each selectively activated via a demultiplexed write gate signal. The selective activation allows for pulsed operation of the heat source resulting in reduced duty cycle and temperature during a write operation.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes a read circuit and a combining circuit. The read circuit is operable to provide a first instance of a user data set, a second instance of the user data set, and a third instance of the user data set. The combining circuit is operable to: combine at least a first segment of the first instance of the user data set with a first segment of the second instance of the user data set to yield a first combined data segment; provide a second combined data set that includes a combination of one or more second segments from the second instance of the user data set and the third instance of the user data set; and provide an aggregate data set including at least the first combined data set and the second combined data set. The second combined data set does not incorporate a second segment of the first instance of the user data set.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit having a data detection circuit is disclosed that includes: a scaling circuit, a soft output calculation circuit, and a factor calculation circuit. The scaling circuit is operable to scale a branch metric value by a scaling factor to yield a scaled output. The soft output calculation circuit is operable to calculate a soft output based at least in part on the scaled output. The factor calculation circuit operable to modify the scaling factor based at least in part on the soft output.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is disclosed that includes an equalizer circuit and a data detection circuit. The equalizer circuit is operable to filter a series of samples based at least in part on a filter coefficient and to provide a corresponding series of filtered samples. The data detection circuit includes: a core data detector circuit and a coefficient determination circuit. The core data detector circuit is operable to perform a data detection process on the series of filtered samples and to provide a most likely path and a next most likely path. The coefficient determination circuit operable to update the filter coefficient based at least in part on the most likely path and the next most likely path.

Abstract: A data signal comprising an even component and an odd component with differing amplitudes is received at a main automatic gain controller (AGC). The even component is adjusted by a first interleaved AGC and the odd component is adjusted by a second interleaved AGC such that even and odd component amplitudes are substantially equal. Amplitude adjusted even and odd components are recombined to define a data signal with components having substantially equal amplitudes. The even and odd components can be generated by a read transducer moving relative to a magnetic storage medium comprising tracks defined by discrete and spaced-apart recording bits arranged in an interspersed pattern. A read channel separates the data signal into even and odd samples such that a gain can be independently adjusted for each of the even and odd samples to compensate for asymmetry between the even and odd samples.

Abstract: A method in one embodiment includes receiving a command to perform at least one of a refresh operation and a verification operation on a media cartridge having a tape wrapped around a spool; mounting the media cartridge in a tape drive; starting execution of the refresh and/or verification operation; aborting execution of the refresh and/or verification operation upon occurrence of a predetermined event. A method in another embodiment includes receiving an instruction to perform a verification operation on a media cartridge having a tape wrapped around a spool; unwrapping at least some of the tape from the spool; after the unwrapping, wrapping at least some of the tape back onto the spool; during at least one of the unwrapping and wrapping, performing a verification operation; terminating execution of the verification operation when a drive error is detected; outputting an indication of a media error when a media error is encountered.

Abstract: Provided are a method, servo channel, and tape drive for determining a reference waveform used by a correlator in a servo channel. Sequences of servo signal samples are provided from read servo signals read from a servo pattern on a recording medium. A determination is made of a reference waveform based on the sequences of servo signal samples and the reference waveform is forwarded. Interpolated servo signals are generated. The interpolated servo signal samples and the forwarded reference waveform are received to generate correlation output samples. Position and velocity information are calculated from the correlation output samples.

Abstract: Various embodiments of the present invention provide systems and methods for detecting contact. For example, a method for detecting head contact is disclosed that includes: receiving an interface signal operable to indicate a physical contact between a sensing device and a storage medium; band pass filtering a data set derived from the interface signal to yield a band pass filtered output; comparing the band pass filtered output to a level threshold to yield a comparator output; summing the comparator output with at least one prior instance of the comparator output to yield an aggregated value; and comparing the aggregated value to an aggregate threshold to yield a contact output.

Abstract: Changes in the thermal boundary condition near a close point of an ABS to a media indicate proximity of the ABS with the media. Before contact, heat conduction from the ABS is primarily through convective and/or ballistic heat transfer to air between the ABS and the media. After contact, heat flux primarily flows from the ABS to the media through solid-solid conductive contact. Further, a light source within a HAMR transducer head may create additional thermal variations within the transducer head. These thermal variations create temperature variations within the transducer head. Two resistance temperature sensors on the transducer head at varying distances from the close point and/or light source measure these temperature variations. A temperature difference between the two resistance temperature sensors indicates proximity of the close point to the media and/or light output.

Abstract: A sequential information storage medium, comprising a plurality of servo patterns encoded lengthwise thereon, wherein each servo pattern encodes at least one LPOS bit and comprises a width less than 187 microns.

Abstract: A patterned medium inspection method according to the present invention includes a timing computation process including a read process reading the reproduced signal of a patterned medium under inspection and a computation process computing the signal interval values from the patterned medium reproduced signal read in the read process, and a judgment process judging the quality of the patterned medium using the reproduced signal interval values computed in the computation process.