A plurality of configuration sets are used with a detector coupled to a decoder. A processor is coupled to the memory registers and the detector and operable to load a first one of the configuration sets into the detector. The detector to attempts detection of the bits in the digital stream for a first iteration between the detector and the decoder using the first configuration set. After the first iteration, a second one of the configuration sets is loaded into the detector. The second configuration set is different than the first configuration set. The detector to attempts detection of the bits in the digital stream for a second iteration between the detector and the decoder using the second configuration set.

An embodiment of a data-read path includes a defect detector and a data-recovery circuit. The defect detector is operable to identify a defective region of a data-storage medium, and the data-recovery circuit is operable to recover data from the data-storage medium in response to the defect detector. For example, such an embodiment may allow identifying a defective region of a data-storage disk caused, e.g., by a scratch or contamination, and may allow recovering data that was written to the defective region.

In an aspect, an apparatus for attribute path generation is presented. An apparatus includes at least a processor and a memory communicatively connected to the at least a processor. A memory contains instructions configuring at least a processor to receive user data. At least a processor configured to identify a plurality of attributes of user data. At least a processor is configured to compare an attribute to an improvement threshold. At least a processor is configured to determine an objective as a function of a comparison. At least a processor is configured to create an attribute path including an objective. The attribute path may be displayed to a user by way of a metamap.

There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.

There is provided a signal processing apparatus and a signal processing method capable of allowing data recorded at a high density to be robustly reproduced. A frame sync (FS) is restored by performing maximum likelihood decoding of the FS according to a time-varying trellis with a state and a state transition being limited according to a time, in maximum likelihood decoding of a reproduction signal reproduced from a disk-shaped recording medium, the FS representing a head of a frame, the FS of the frame being arranged at the head of the frame, the FS being recorded at the same positions in a track direction in two adjacent tracks.

A system for compensating RI while reading servo data from a rotating storage medium is provided and includes an equalizer, a Viterbi detector, and a servo control module. The equalizer receives a digital signal including a bit sequence of the servo data read from the rotating storage medium and equalizes the digital signal via filters. Some of the filters are to phase rotate the digital signal to generate phase rotated signals. The Viterbi detector operates based on a Viterbi state machine, which includes main branches having sub-branches, where: each of the main branches is to receive the phase rotated signals respectively at corresponding ones of the sub-branches; and the Viterbi detector is to determine branch metrics for each of the sub-branches, determine a minimum branch metric for each of the main branches, and process the minimum branch metric using an add-compare-select process to determine a most likely received bit sequence.

There are provided an optical disk from which high-density data is reproduced and a reproduction apparatus that reproduces data from such an optical disk having high-density data recorded thereon. A photo-detecting section has two split detectors A and B in the direction of tracks on the disk. A signal processing section generates a TPP (Tangential Push-pull) signal made of a differential signal derived from detection signals from the detectors A and B, and further generates a reproduced signal by extracting from the TPP signal a high-frequency component signal in a record signal recorded on the disk. The signal processing section reconstitutes a high-frequency component signal in the record signal recorded on the disk by frequency-shifting the TPP signal obtained as a readout signal from a superimposed signal having the carrier signal and the record signal superimposed with each other.

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.

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.