An apparatus and associated method contemplating a head gimbal assembly (HGA) and a bridge circuit including first and second microactuators attached to the HGA. Computation logic is connected to the bridge circuit and configured to independently measure an electrical output of each microactuator and to sum the electrical outputs to derive a value related to a vertically dominant modulation mode of the HGA.

Systems and methods relating generally to data processing, and more particularly to adjusting gain parameters in relation to data processing.

Methods and devices for coherent holographic data channel techniques. Coherent techniques for data detection generally include homodyne and heterodyne detection. Techniques for quadrature homodyne detection, resampling quadrature homodyne detection, n-rature homodyne detection, and spatial wavefront demodulation. Coherent detection techniques in turn enable coherent channel modulation techniques such as phase modulation (including binary phase shift keying, or BPSK; phase quadrature holographic multiplexing, or QPSK; and quadrature amplitude modulation, or QAM). Coherent detection may also enable or improve the performance of other channel techniques such as partial response maximum likelihood (PRML), the various classes of extended PRML, and of noise-predictive maximum likelihood (NPML) detection.

An apparatus for two-dimensional magnetic recording includes an array reader comprising a number of read sensors configured to read data from at least one track on a storage medium, a number of two-dimensional equalizer circuits each comprising inputs for receiving signals derived from each of the read sensors, each comprising an equalized output, and a number of iterative inter-track interference cancellation circuits, each operable to cancel inter-track interference in a different one of the equalized outputs from the two-dimensional equalizer circuits.

An apparatus for processing data includes a data detector configured to detect data values in data sectors to yield detected data, a data decoder configured to decode the detected data, wherein the data detector and the data decoder are configured to process the data sectors in a series of global iterations, a memory configured to store parity sector soft information, and a scheduler configured to control overlapping reprocessing of a failed sector in the data detector and the data decoder based on the parity sector soft information with processing of another data sector in the data detector and the data decoder.

A data storage device is disclosed comprising a non-volatile memory (NVM). During a read operation, a sequence of signal samples is generated representing codewords stored in the NVM. The signal samples are buffered to generate buffered signal samples. The buffered signal samples are processed at a first frequency to detect a data sequence, and a bottleneck condition is detected associated with processing the buffered signal samples at the first frequency. When the bottleneck condition is detected, the buffered signal samples are processed at a second frequency higher than the first frequency to detect the data sequence.

According to one embodiment, a magnetic disk device includes a disk, a head configured to write data to and read data from the disk, and a controller configured to compress data transmitted with a specific size into compressed data, add data of a first pattern to the compressed data to generate first data having the specific size, execute an encoding process to the generated first data, output second data obtained by encoding the first data, and execute a decoding process to the second data input from outside based on the first pattern.

A data object has a lock and a condition indicator associated with it. Based at least partly on detecting a first setting of the condition indicator, a reader stores an indication that the reader has obtained read access to the data object in an element of a readers structure and reads the data object without acquiring the lock. A writer detects the first setting and replaces it with a second setting, indicating that the lock is to be acquired by readers before reading the data object. Prior to performing a write on the data object, the writer verifies that one or more elements of the readers structure have been cleared.

A method of reading data from a rotating magnetic storage medium, having at least one read head, includes storing respective digitized data samples from each respective read head of the at least one read head in a respective timing buffer, determining a zero-phase start phase angle from a preamble of the digitized data samples, feeding forward the zero-phase start phase angle to an interpolator, selecting an interpolation filter based on the fed-forward zero-phase start phase angle, releasing the respective digitized data from the respective timing buffer after a duration sufficient for completion of the determining, the feeding forward and the selecting, and interpolating samples of the digitized data released from the respective timing buffer.

Embodiments of the present inventions are related to systems and methods for data processing, and more particularly to systems and methods for recovering data where synchronization information is not detected.