Abstract: In a disk storage system, the disk may include a full null servo position error signal (“PES”) wedge, followed by a data wedge, and then a short null servo PES wedge. To improve the accuracy with which information read from the short null servo PES wedge can be used to help keep the read head centered over the information track being read, the short null servo PES wedge may include a calibration field. Information read from the calibration field can be used to compensate the subsequently read PES information in the short wedge for possible sampling phase error that may have accumulated since the full null servo PES wedge was read. This type of short null servo PES wedge also has other possible uses.

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 storage controller includes a device controller and a read data channel. The read data channel includes a decoder for decoding output of a detector, where the detector is for reading data requested from a storage medium by the device controller, and the storage medium has a plurality of tracks of data thereon. When the device controller requests data from a current track of data on the storage device, the detector reads an adjacent track of data, the decoder decodes data from the adjacent track of data, the detector reads data from the current track, and the decoder decodes the data read from the current track, based on the decoded and stored data from the adjacent track of data. A storage system includes a storage medium having a plurality of tracks of data thereon and a storage controller as described above.

Abstract: Techniques are provided for performing bit-locked operations on media. A first control signal is received from a first source, and a second control signal is generated at a second source in response to receiving the first control signal. The media is accessed according to the second control signal. One or more synchronization markers are located during the accessing of the media, and bit-level synchronization between the second source and the media is achieved based, at least partially, on the one or more synchronization markers. A control operation is performed on the media with bit-level synchrony between the second source and the media.

Abstract: A process is disclosed for determining one or more edges of usable portions of a disk drive. Such knowledge can be used to determine the range of valid tracks of the disk and improve utilization of available disk space. The process can detect the edges by processing one or more disk controller signals, such as an adaptive feed-forward (AFC) injection signal, or a position error signal (PES).

Abstract: A write clock synchronization system includes a first module configured to generate a write clock signal. A second module is configured to, based on a sensor signal received, detect a pattern of bit islands on bit-patterned media. The second module is configured to determine a phase error of the write clock signal based on the pattern of the bit islands. A third module is configured to at least one of adjust or select a phase of the write clock signal based on the phase error.

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 and a bias calculation circuit. The data detector circuit is operable to apply a data detection algorithm to a first data set to yield a first series of soft decision data, and to apply the data detection algorithm to a second data set to yield a second series of soft decision data. The bias calculation circuit operable to calculate a series of bias values based at least in part on the first series of soft decision data and the second series of soft decision data. The series of bias values correspond to a conversion between the first series of soft decision data and the second series of soft decision data.

Abstract: The present inventions are related to systems and methods for transferring information to and from a storage medium, and more particularly to systems and methods for positioning a sensor in relation to a storage medium. For example, an apparatus for determining a sensor position is disclosed that includes a data stream processor operable to generate a number of data streams at different frequencies based on an input data stream, a number of servo preamble detectors each operable to process a different one of the data streams to detect a servo preamble, a selector operable to output one of the data streams in which the servo preamble was detected as a winning data stream, and a pattern detector operable to detect a pattern in the winning data stream.

Abstract: Embodiments described herein provide for robust servo patterns that comply with planarization constraints and also allow use of a single master template for manufacture of both the front and back of a magnetic disk. Planarization constraints are met because only a portion of servo data is hard patterned on the magnetic disk and the hard patterned servo data areas comply with planarization constraints. The servo pattern has two symmetrical servo write assist patterns, one on each side of a central burst pattern. The servo sync, SAM, track-ID, sector-ID, and/or RRO values can be written magnetically by the write head onto these servo write assist patterns after the completion of the planarization process. The symmetric design of the servo pattern allows both a left-to-right and a right-to-left servo write and read back, thereby enabling use of a single master template in magnetic disk manufacture.

Abstract: A “write-squeeze-verify” method is used for verification of the data that has been written in the annular bands of a shingled magnetic recording disk drive. The writing of data along a track overwrites a portion of the previously written track and thus “squeezes” the data of the previously written track to thereby form a “shingled data track” (SDT). The data in each SDT is read back and verified by an error correction check using error correction bits associated with the data written in the SDT, or by comparing the readback data with the data stored in memory. If the data read back is not verified, a write error counter is incremented and a write error frequency is calculated. One or more attempts to write the data can be performed. If the data in the SDT cannot be verified after the attempted rewrite(s), then a “re-try fail” is reported.

Abstract: A method, apparatus, and system are provided for implementing spin-torque oscillator (STO) sensing with a demodulator for hard disk drives. The demodulator measures an instantaneous phase of the readback signal from a STO sensor and converts the readback signal into a signal that is proportional to the magnetic field affecting the STO frequency during a bit time. The converted signal is used for processing by conventional data detection electronics.

Abstract: The present disclosure includes systems and techniques relating to control of magnetic recording devices, such as disk drives. Systems and techniques include generating timing data based on a waveform produced by a head operated with respect to a magnetic rotating recording medium; operating a model-based predictor based on model parameters to produce one or more model-based predictor outputs to compensate for deterministic disturbances in an area situated on a portion of a track on the recording medium; operating a stochastic predictor based on the timing data to produce one or more stochastic predictor outputs to compensate for nondeterministic disturbances in the area; and performing one or more clock frequency adjustments that are responsive to the head being operated within the area, the one or more clock frequency adjustments being based on the one or more model-based predictor outputs and the one or more stochastic predictor outputs.

Abstract: A method of calculating a Head Media Separation (HMS) from a preamble of embedded servo sectors in a disk drive may include steps of reading the preamble, the read preamble being amplified by a variable gain amplifier (VGA) set at a predetermined gain; transforming samples of the read preamble into a first and a second frequency using a discrete time-to-frequency domain transform such as a Discrete Fourier Transform (DFT); calculating the ratio of the magnitude of the discrete time-to-frequency domain transform of the first frequency to the magnitude of the discrete time-to-frequency domain transform of the second frequency; determining the HMS from the calculated ratio, and enabling the predetermined gain to be updated in synchronism with the transforming step.

Abstract: A device and a method for controlling a bit density of a magnetic card (2) are provided. Said control device comprises a stepper motor (1) providing power to drive the magnetic card (2) or a recording magnetic head (15), a transmission mechanism transferring power to the magnetic card (2) or the recording magnetic head (15), a CPU (10) sending magnetic recording information, a track data encoder (13) receiving a magnetic writing pulse signal (CLK1) and generating magnetic writing data in synchronization with the magnetic writing pulse signal (CLK1), and a magnetic head driving circuit (14) outputting a magnetic writing control signal based on the magnetic writing data. The frequency of the magnetic writing pulse signal (CLK1) and the frequency of a driving pulse signal (CLK0) of the stepper motor are in a linear relationship. Said control method is a method for controlling a bit density.

Abstract: An information handling system includes a free fall sensing system having an amplifier and sampling circuit, a sampling data analyzer, a sampling clock duration controller, and a sampling clock generator. The amplifier and sampling circuit is configured to sample data signals from the free fall sensor based on an initial sampling signal and based on a variable sampling signal. The sampling data analyzer is configured to compare a magnitude of sampled data point to a predetermined magnitude, to output an alert signal when the magnitude of the sampled data point is below the predetermined magnitude. The sampling clock duration controller is configured to vary a duration and a frequency of a sampling signal control in response to the alert signal. The sampling clock generator is configured to send a variable sampling signal to the amplifier and sampling circuit in response to the variation of the duration and the frequency of the sampling signal control.

Abstract: According to one embodiment, a magnetic recording medium includes a substrate, an auxiliary layer formed on the substrate, and at least one perpendicular magnetic recording layer formed on the auxiliary layer. The perpendicular magnetic recording layer includes a magnetic dot pattern. The perpendicular magnetic recording layer is made of an alloy material containing one element selected from iron and cobalt, and one element selected from platinum and palladium. This alloy material has the L10 structure, and is (001)-oriented. The auxiliary layer includes a dot-like first region covered with the magnetic dot pattern, and a second region not covered with the magnetic dot pattern. The first region is made of one metal selected from (100)-oriented nickel and (100)-oriented iron. The second region contains an oxide of the metal used in the first region.

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: Various embodiments of the present invention provide apparatuses, systems and methods for data detection in a detector with a pruning control system. For example, a data detector is disclosed that includes a first set of counters operable to distinguish prunable data from non-prunable data in the data detector, a second set of counters operable to generate initial values for the first set of counters, and a prune control signal generator operable to generate a prune control signal based on the first set of counters. The second set of counters is operable to generate the initial values at least in part before a syncmark is detected in a data sector. The initial values are used to initialize the first set of counters when the syncmark is detected in the data sector. The prune control signal controls whether the data detector is allowed to prune a trellis.

Abstract: An apparatus comprises a root mean square (‘RMS’) value generator; an integrator coupled to the RMS value generator; a sample and hold switch coupled to an output of the integrator; a capacitor coupled between the sample and hold switch and a ground; an input of the analog to digital convertor (‘ADC’) coupled to the capacitor; an adder coupled to an output of the ADC; a register, wherein an output of the register is coupled to an input of the adder; and wherein an output of the adder is coupled to an input of the register; and a logic coupled to the register for comparing an output of the register to an RMS threshold value for determining whether a touch-down has occurred.