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: Various embodiments of the present invention provide systems and methods for data processing. For example, a method for data processing is disclosed that includes: receiving a data input having at least a first local chunk and a second local chunk, the data input also being defined as having at least a first global chunk and a second global chunk; rearranging an order of the first local chunk and the second local chunk to yield a locally interleaved data set; storing the locally interleaved data set to a first memory, such that the first global chunk is stored to a first memory space, and the second global chunk is stored to a second memory space; accessing the locally interleaved data set from the first memory; and storing the locally interleaved data set to a second memory. The first global chunk is stored to a third memory space defined at least in part based on the first memory space, and the second global chunk is stored to a fourth memory space defined at least in part based on the second memory space.

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 gating circuit.

Abstract: Various embodiments of the present invention provide systems and methods for event alignment control. For example, an event alignment control circuit is disclosed that includes a delay table, a flag write controller circuit, and a signal reconstruction circuit. The delay table includes at least a first register and a last register, and is operable to transfer data from the first register to the last register. The flag write controller circuit is operable to receive an indication of assertion of an event flag and to write information relevant to the event flag to the first register of the delay table. The signal reconstruction circuit is electrically coupled to the last register, and reconstructs the event flag based at least in part on the information relevant to the event flag obtained from the last register.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. A data processing circuit is disclosed that includes: a data detector circuit, a first symbol constrained arrangement circuit, and a second symbol constrained arrangement circuit. The data detector circuit is operable to apply a data detection algorithm to a combination of a first input data set and a decoded data set to yield a detected output that includes a number of non-binary symbols. The first symbol constrained arrangement circuit is operable to receive the detected output and to re-arrange the detected output in accordance with a first arrangement algorithm to yield a re-arranged output. The bits for at least one non-binary symbol from the detected output are maintained together in the re-arranged 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 a data detecting circuit having: a first vector translation circuit, a second vector translation circuit, and a data detector core circuit. The data detecting circuit is operable to receive an input data set and at least one input vector in a first format. The at least one input vector corresponds to a portion of the input data set. The first vector translation circuit is operable to translate the at least one vector to a second format. The data detector core circuit is operable to apply a data detection algorithm to the input data set and the at least one vector in the second format to yield a detected output. The second vector translation circuit operable to translate a derivative of the detected output to the first format to yield an output vector.

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 data detector circuit, a data decoder circuit, and a power monitor circuit. The data detector circuit is operable to apply a data detection algorithm to a data input and a decoded output to yield a detected output. The data decoder circuit is operable to apply a data decoding algorithm to the detected output to yield the decoded output. The power monitor circuit is operable to receive a first power status signal from the data detector circuit and a second power status from the data decoder circuit, and to calculate a power usage of a combination of at least the data detector circuit and the data decoder circuit.

Abstract: The present invention is a programmable QC LDPC encoder for encoding user data. The encoder may be configurable for implementation with a read channel. The encoder may include a plurality of barrel shifter circuits. The barrel shifter circuits are configured for generating a plurality of parity bits based on interleaved user bits received by the encoder. The barrel shifter circuits are further configured for outputting the parity bits. The encoder may further include an encoder interleaver memory. The encoder interleaver memory may be communicatively coupled with the barrel shifter circuits and may receive the parity bits output from the barrel shifter circuits. The encoder interleaver may be configured for interleaving the parity bits. Further, the encoder may be configured for outputting the interleaved parity bits to a multiplexer. The barrel shifter circuits may generate the plurality of parity bits via an encoding algorithm: p=u*GT.

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 selecting between pre-coding and non-pre-coding. As an example, a data processing circuit is disclosed that includes: a first data detector circuit, a second data detector circuit, a first comparator circuit, a second comparator circuit, and a pre-code selection circuit. The first data detector circuit is selectably configurable to operate in a pre-coded state, and operable to apply a data detection algorithm on a data input to yield a first detected output. The second data detector circuit operable to apply the data detection algorithm to the data input to yield a second detected output without compensating for pre-coding. The first comparator circuit operable to compare the first detected output against a known input to yield a first comparison value, and the second comparator circuit operable to compare the second detected output against the known input to yield a second comparison value.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing circuit is disclosed that includes an increased iteration enable signal, a first detector circuit, a second detector circuit, and a data decoding circuit. The first detector circuit receives a data set and performs a data detection on the data set to provide a detected data set. The data decoding circuit receives a derivative of the detected data set and performs a decoding process to provide a decoded data set. The decoded data set is provided to the second detector circuit based at least in part on an assertion level of the increased iteration enable signal.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a variable iteration data processing system is disclosed that includes a first detector, a second detector, a decoder and a unified memory buffer. An input data set is received by the first detector that performs a data detection and provides a first detected data set. The decoder receives a derivative of the first detected data set and performs a decoding operation that yields a decoded data set. In some cases, the derivative of the first detected data set is an interleaved version of the first detected data set. The decoded data set is written to a unified memory buffer. The first decoded data set is retrievable from the unified memory buffer and a derivative thereof is provided to the second detector. In some cases, the derivative of the decoded is a de-interleaved version of the decoded data set.

Abstract: In exemplary embodiments, a skewed interleaving function for iterative code systems is described. The skewed interleaving function provides a skewed row and column memory partition and a layered structure for re-arranging data samples read from, for example, a first channel detector. An iterative decoder, such as an iterative decoder based on a low-density parity-check code (LDPC), might employ an element to de-skew the data from the interleaved memory partition before performing iterative decoding of the data, and then re-skew the information before passing decoded samples to the de-interleaver. The de-interleaver re-arranges the iterative decoded data samples in accordance with an inverse of the interleaver function before passing the decoded data samples to, for example, a second channel detector.

Abstract: Various embodiments of the present invention provide systems and methods for data regeneration. For example, a method for data regeneration is disclosed that includes receiving a data input derived from a medium, determining a media defect corresponding to the data input, and determining an attenuation factor associated with the defective medium. Based at least in part on the determination that the medium is defective, amplifying the data input by a derivative of the attenuation factor to regenerate the data.

Abstract: In one embodiment, an LDPC decoder has a controller and an extrinsic log-likelihood (LLR) value generator. The extrinsic LLR value generator is selectively configurable to operate in either (i) a non-averaging mode that updates extrinsic LLR values without averaging or (ii) an averaging mode that updates extrinsic LLR values using averaging. Initially, the extrinsic LLR value generator is configured to generate non-averaged extrinsic LLR values, and the decoder attempts to recover an LDPC-encoded codeword using the non-averaged extrinsic LLR values. If the decoder is unable to recover the correct codeword, then (i) the controller selects the averaging mode, (ii) the extrinsic LLR value generator is configured to generate average extrinsic LLR values, and (iii) the decoder attempts to recover the correct codeword using the average extrinsic LLR values. Averaging the extrinsic LLR values may slow down the propagation of erroneous messages that lead the decoder to convergence on trapping sets.

Abstract: Various embodiments of the present invention provide systems and methods for updating detector parameters in a data processing circuit. For example, a data processing circuit is disclosed that includes a first detector circuit, a second detector circuit, and a calibration circuit. The first detector circuit is operable to receive a first data set and to apply a data detection algorithm to the first data set, and the second detector circuit is operable to receive a second data set and to apply the data detection algorithm to the second data set. The calibration circuit is operable to calculate a data detection parameter based upon a third data set. The data detection parameter is used by the first detector circuit in applying the data detection algorithm to the first data set during a period that the data detection parameter is used by the second detector circuit in applying the data detection algorithm to the second data set.

Abstract: Various embodiments of the present invention provide systems and methods for monitoring out of order data decoding. For example, a method for monitoring out of order data processing is provided that includes receiving a plurality of data sets that is associated with a plurality of identifiers with each of the plurality of identifiers indicates a respective one of the plurality of data sets; storing each of the plurality of identifiers in a FIFO memory in an order that the corresponding data sets of the plurality of data sets was received; processing the plurality of data sets such that at least one of the plurality of data sets is provided as an output data set; accessing the next available identifier from the FIFO memory; and asserting an out of order signal when the next available identifier is not the same as the identifier associated with the output data set.

Abstract: In a communications system that demultiplexes user data words into multiple sub-words for encoding and decoding within different subword-processing paths, the minimum distance between bit errors in an extrinsic codeword can be increased by having corresponding subword encoders/decoders in the different subword-processing paths perform subword encoding/decoding with different encoder/decoder matrices.

Abstract: Various embodiments of the present invention provide systems and methods for data processing. For example, a data processing circuit is disclosed that includes an increased iteration enable signal, a first detector circuit, a second detector circuit, and a data decoding circuit. The first detector circuit receives a data set and performs a data detection on the data set to provide a detected data set. The data decoding circuit receives a derivative of the detected data set and performs a decoding process to provide a decoded data set. The decoded data set is provided to the second detector circuit based at least in part on an assertion level of the increased iteration enable signal.

Abstract: Various embodiments of the present invention provide systems and methods for event alignment control. For example, an event alignment control circuit is disclosed that includes a delay table, a flag write controller circuit, and a signal reconstruction circuit. The delay table includes at least a first register and a last register, and is operable to transfer data from the first register to the last register. The flag write controller circuit is operable to receive an indication of assertion of an event flag and to write information relevant to the event flag to the first register of the delay table. The signal reconstruction circuit is electrically coupled to the last register, and reconstructs the event flag based at least in part on the information relevant to the event flag obtained from the last register.