Lsi Corporation

Avago Technologies General IP (singapore) Pte. Ltd.

Agere Systems Inc.

Scott M Dziak

Haitao Xia

Jason D Byrne

Richard Rauschmayer

Nayak Ratnakar Aravind

Ming Jin

Jeffrey Paul Grundvig

Kurt J Worrell

George Mathew

Weijun Tan

Haotian Zhang

Jefferson E Singleton

Yang Cao

Siva Swaroop Vontela

Erich Franz Haratsch

Bruce Alexander Wilson

Hongwei Song

Yuan Xing Lee

Jingfeng Liu

Lu Lu

Zhi Bin Li

Lu Pan, Sr

Jason S Goldberg

Xiao Yuan Ma

Daniel A Bressan

David L Parker

Bradley D Seago

Jonathan Dykhuis

An apparatus for reading data from a magnetic storage medium includes a plurality of magnetic read heads each configured to read a track of the magnetic storage medium and generate an analog data signal corresponding to the read track. The apparatus includes a converter to generate digital data samples from the analog data signals, and a plurality of equalizers to apply a plurality of coefficients to the digital data samples to generate a plurality of equalized signals. The plurality of coefficients are associated with different locations within the track. The apparatus includes a plurality of detectors to compute metrics and detect data bits for the plurality of equalized signals, and at least one selector to select one of the plurality of equalized signals that has a best metric from the computed metrics and to output the selected equalized signal.

Devices and methods for reading magnetic media

Systems, methods, devices, circuits for data processing, and more particularly to systems and methods for reporting a synchronization indication and for applying a synchronization window. As an example, a system is discussed that includes: a head assembly including a first read head and a second read head; a down track distance calculation circuit operable to calculate a down track distance between the first read head and the second read head; and a synchronization mark detection circuit. The synchronization mark detection circuit is operable to: assert a synchronization mark window based at a location based at least in part on the down track distance; query a first data set derived from the first read head for a synchronization mark occurring within the synchronization mark window; and query a second data set derived from the second read head for the synchronization mark occurring within the synchronization mark window.

Systems and methods for synchronization hand shaking in a storage device

An apparatus for controlling a feedback loop includes a digital finite impulse response filter configured to equalize digital samples to yield equalized data, a data detector circuit configured to detect values of the equalized data to yield detected data, a pattern detection circuit configured to detect at least one pattern in the detected data, an expected value comparison circuit configured to compare the digital samples corresponding to the at least one pattern with an expected value, and a feedback loop adaptation circuit configured to control a feedback loop based in part on whether the at least one pattern is detected by the pattern detection circuit and on an output of the expected value comparison circuit.

Loop adaptation control with pattern detection

A method for calculating an average phase offset in a two dimensional magnetic recording system includes calculating a phase offset as a difference between a phase of a first signal derived from a first read head and a second phase of a second signal derived from a second read head, correcting for phase wrapping differences between the phase offset and a previous phase offset, determining whether the phase offset is consistent with the previous phase offset, and calculating an average phase offset which includes the phase offset only if it is consistent with the previous phase offset.

Two dimensional magnetic recording head separation calculator

Embodiments are related to systems and methods for data processing, and more particularly to systems and methods for format efficient processing of data fragments.

Systems and methods for format efficient sector fragment processing

Various embodiments of the present invention provide systems and methods for estimating signal and noise powers in a received signal set. For example, one embodiment of the present invention provides a method for determining signal power and noise power. The method uses a storage medium that includes a N&#xd7;Ndata pattern. The N&#xd7;Ndata pattern includes Nbits repeated Ntimes. Both Nand Nare each greater than one. The methods further include performing an initial read of the N&#xd7;Ndata pattern, which is stored to a first register. Nsubsequent reads of the N&#xd7;Ndata pattern are each processed by: performing a subsequent read of the N&#xd7;Ndata pattern, and performing a difference calculation using the initial read of the N&#xd7;Ndata pattern and the subsequent read of the N&#xd7;Ndata pattern and resulting in the calculation of a difference vector that is stored to a second register; and performing a difference accumulation calculation to generate an accumulation vector which is stored to a third register. Based at least in part on the stored N&#xd7;Ndata pattern and the stored difference vector, an electronics noise power is calculated.

Systems and methods for memory efficient signal and noise estimation

An exemplary hard disk (HD) track has a full overhead section followed by user sections interleaved with intervening partial overhead sections that are too short for an HD drive (HDD) to attain sufficient timing lock using only one partial overhead section, but long enough for the drive to attain sufficient timing lock using multiple partial overhead sections to read user data from the user section immediately following the partial overhead section where sufficient timing lock is attained. The drive begins, but does not finish, attaining timing lock based on the first partial overhead section, but the drive does finish attaining timing lock based on the last partial overhead section. The drive can also read user data in subsequent user sections by maintaining or re-attaining sufficient timing lock using each successive partial overhead section. Increased user data storage is achieved without significantly impacting average latency of HDD read sessions compared to conventional HD drives.

Reading data from hard disks having reduced preambles

A system for accessing a data from a storage device includes a gain value calculation circuit operable to calculate a first gain value based upon a data set, an early gain acquisition circuit operable to generate a second gain value in parallel to calculation of the first gain value by the gain value calculation circuit, and a gain combination circuit operable to combine the first gain value and the second gain value to yield a third gain value.

Automatic gain control with early acquisition

A method and system for detecting an end of a preamble without interpolation. The method includes receiving information from a zero phase start module, the information including a target phase constraint, a polyant, and a zero phase start phase. The method also includes selecting two samples per preamble cycle of short filter outputs and long filter outputs based on the target phase constraint, the polyant, and the zero phase start phase. The method further includes decimating the short filter outputs and the long filter outputs such that the selected two samples for each of the filters per preamble cycle are output upon decimation. The method additionally includes performing a sign comparison on the corresponding short filter and long filter outputs after decimation, wherein a sign mismatch of the corresponding short filter and long filter outputs indicates an end of a preamble.

Detection of end of preamble in read channel without interpolation

A method and system for performing a shortened acquire cycle for at least one fragment of at least one data sector having coherently written fragments, the coherently written fragments being written during a single rotation of a storage medium. The method includes performing a full acquire cycle for a first fragment of a particular data sector of the at least one data sector. The method further includes reusing at least a portion of the acquisition information of the first fragment to perform a shortened acquire cycle for at least one subsequent coherently written fragment. The method also includes reusing at least a portion of the acquisition information of the first fragment to perform a shortened acquire cycle for at least one subsequent coherently written fragment. Additionally, the method includes performing the shortened acquire cycle for the at least one subsequent coherently written fragment.

Method for format savings in coherently written fragmented sectors

A method and system for providing format savings in data sectors. The method includes receiving a signal outputted from an analog-to-digital conversion circuit. The method further includes shifting a signal phase of the signal based at least upon a corrected phase at an output of a phase loop and a phase measured when the signal was digitally sampled by the analog-to-digital conversion circuit. The method also includes adjusting a gain of the signal based at least upon a current gain loop correction and a gain correction made when the signal was digitally sampled by the analog-to-digital conversion circuit. Additionally, the method includes adjusting the signal based at least upon an output of a current offset correction and an offset correction made when the signal was digitally sampled by the analog-to-digital conversion circuit. The method also includes outputting an adjusted signal to a sync mark detector.

Method of format savings via predictive correction of synchronization word

The disclosure is directed to a system and method of determining signal quality based upon at least one of: a comparison of energy content of the signal to a threshold energy content, a comparison of energy content of the fundamental harmonic of the signal to a specified percentage of the energy content of the signal, and a comparison of a difference between phase of the signal and a target phase to a threshold phase difference.

System and method for monitoring preamble signal quality

Various embodiments of the present invention provide systems and methods for media defect detection. For example, a media defect detection systems is disclosed that includes a data input derived from a medium, a fast envelope calculation circuit that receives the data input and provides a fast decay envelope value based on the data input, a slow envelope calculation circuit that receives the data input and provides a slow decay envelope value based on the data input, and a media defect detection circuit. The media defect detection circuit receives the slow decay envelope value and the fast decay envelope value, calculates a ratio value of the fast decay envelope value to the slow decay envelope value, and asserts a defect output based at least in part on the comparison of the ratio value to a defect threshold value.

Systems and methods for low latency media defect detection

An apparatus for detecting media flaws includes an envelope based media defect detector operable to identify a media defect based on an envelope of an input signal, a periodic pattern detector operable to determine whether the input signal comprises a data pattern, and a media flaw signal generation circuit operable to indicate a media defect when the envelope based media defect detector identifies the media defect and the periodic pattern detector determines that the input signal does not comprise the data pattern.

Systems and methods for media defect detection with pattern qualification

Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing circuit is disclosed that includes first and second data detectors and an error cancellation circuit. The first data detector is operable to perform a data detection process on a first signal derived from a data input to yield a detected output. The second data detector circuit is operable to perform a data detection process on a second signal derived from the data input to yield a second detected output. The error cancellation circuit is operable to combine a first error signal derived from the detected output with a second error signal derived from the second detected output to yield a feedback signal. The feedback signal is operable to modify the data input during a subsequent period.

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Longmont, CO, United States of America

Scott M Dziak