Systems and methods are disclosed for detecting shingled overwrite errors. When a read error is encountered when reading from shingled recording tracks, a processor may determine whether the read error is an error caused by shingled overwriting. The processor may determine whether the read error is caused by shingled overwriting by determining read signal quality of one or more sectors preceding the read error, such as based on a bit error count or bit error ratio (BER), and comparing the read signal quality to a threshold value. The processor may determine that the read error is caused by shingled overwriting when the read signal quality value is lower than the threshold.

A set of first signal light and reference light with a phase difference of almost 0 degree, a set of second signal light and reference light with a phase difference of almost 180 degrees, a set of third signal light and reference light with a phase difference of almost 90 degrees, and a set of fourth signal light and reference light with a phase difference of almost 270 degrees are generated. A first differential signal as a difference between a first light-receiving signal obtained by a first light-receiving element and a second light-receiving signal obtained by a second light-receiving element is calculated, and a second differential signal as a difference between a third light-receiving signal obtained by a third light-receiving element and a fourth light-receiving signal obtained by a fourth light-receiving element is calculated. The first differential signal and the second differential signal are supplied to respective FIR filters. An equalization error is formed from output signals from the FIR filters. Tap coefficients for the FIR filters are controlled to minimize the equalization error.

A system comprises a writer to form a plurality of color mits on a base material, wherein at least one of the color mits may represent computer-readable instructions comprising data other than pixel-image data. The plurality of color mits may include a first color mit and a second color mit, wherein the first color mit represents information data, and the second color mit represents that the first color mit contains a particular type of information data. The system also may include a reader to read colors of the plurality of color mits on the base material. The system may comprise a device to map at least one of the color mits to computer-readable instructions. The system may further comprise a processor configured to transmit signals using a colored light.

A method of decoding a codeword that satisfies a k constraint into output data includes, using a decoder of a hard disk drive system, converting each bit of the codeword in Non-Return-to-Zero format, extracting, from the converted codeword, a plurality of data blocks comprising a first data block and a plurality of remaining data blocks, performing a first analysis on the plurality of data blocks for modifying each of the plurality of data blocks that satisfies a first predetermined criterion, and performing a second analysis on the plurality of data blocks after the first analysis for modifying each of the plurality of data blocks that satisfies a second predetermined criterion to obtain the output data.

The presently disclosed technology teaches integrating disc drive electronics into a transducer head. Decreased electrical transit times and data processing times can be achieved by placing the electronics on or within the transducer head because electrical connections may be made physically shorter than in conventional systems. The electronics may include one or more of a control system circuit, a write driver, and/or a data buffer. The control system circuit generates a modified clock signal that has a fixed relation to phase and frequency of a bit-detected reference signal that corresponds to positions of patterned bits on the disc. The write driver writes outgoing data bits received from an external connection to off-head electronics directly to the writer synchronized with the modified clock signal. The data buffer stores and converts digital data bits sent from the off-head electronics to an analog signal that is synchronized with the modified clock signal.

There is provided an optical medium reproduction device that optically reproduces an optical medium in which a plurality of tracks are provided, the optical medium reproduction device including: a detection unit configured to divide a cross-section of a beam returning from the optical medium into at least one channel corresponding to an outer region in a radial direction, at least one channel corresponding to a region that is different in position in a tangential direction, and a channel corresponding to the other region, and form detection signals of the channels; a multi-input equalizer unit including a plurality of equalizer units to which the detection signals of the plurality of channels are supplied, respectively, the multi-input equalizer unit being configured to calculate outputs of the plurality of equalizer units and output the outputs as an equalized signal in a manner that a phase difference between two of the regions is set to be a predetermined phase difference; and a binarization unit configured to perform a binarization process on the equalized signal to obtain binary data.

An apparatus determines that phase errors have exceeded a threshold when reading data previously recorded to a heat-assisted recording medium. In response to the phase errors exceeding the threshold, remedial action is taken to prevent loss of data due changes in power applied to heat the heat-assisted recording medium when recording.

First and second different write precompensation values are associated with different first and second non-return-to-zero, inverted (NRZI) data patterns. The first and second different write precompensation values cause a predetermined phase shift to be written into test data that comprises the first and second NRZI data patterns. The test data is mitten to a recording medium of a storage device using the first and second write precompensation value. The test data is used to determine a response of the storage device to the predetermined phase shift.

Data detection capability is improved by whitening crosstalk noise from an equalization signal and detecting binary data. Each of a plurality of detection signals is input to one of a plurality of adaptive equalizers, and outputs of the plurality of adaptive equalizers are computed to obtain an equalization signal for returning light at the time of shining of light onto bounds including a target track subject to data detection and adjacent tracks of an optical recording medium having a plurality of tracks formed thereon. Crosstalk noise from the adjacent tracks included in the equalization signal obtained by this multi-input adaptive equalization process is whitened first, followed by a binarization process. Also, an equalization error is found, and supplied as a control signal for adaptive equalization. Further, a whitening factor updating process is also performed to adaptively update a filter factor of a whitening filter.

A magnetic recording and reproducing apparatus for recording and reproducing bit information comprising a magnetic head having a spin torque oscillator configured to readout bit information which is recorded on a magnetic recording medium, a detector configured to detect amplitude of a first signal, the first signal which is to reproduce the bit information, and a controller configured to control the magnetic head so as to read the bit information recorded on the magnetic recording medium when the amplitude of the first signal detected by the detector is smaller than a predetermined value.