A method for performing a flaw scan test on a hard disk drive is disclosed. The hard disk drive includes a magnetic recording medium and spindle motor associated with a predetermined rated speed. The method includes writing a test pattern to the magnetic recording medium while operating the spindle motor at a speed greater than the predetermined rated speed. The method also includes reading the test pattern at the greater speed and detecting flaws in response to reading the test pattern.

A computer-implemented method, according to one embodiment, includes: detecting a first error while accessing a magnetic tape, determining a first error location on the magnetic tape where the first error occurred, determining one or more areas on the magnetic tape to be examined, independent of a read and/or write operation, inducing relative motion between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn, using the tape head to measure a number of servo errors that occur in each of the respective one or more areas, and identifying each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value as a damaged area of the magnetic tape. The one or more areas are determined using a predetermined algorithm which incorporates the first error location.

A method for scanning for flaws on a magnetic recording medium is disclosed. The magnetic recording medium has a first set of nonconsecutive data tracks and a second set of nonconsecutive data tracks. The method includes writing a test pattern to only the first set of nonconsecutive data tracks of the magnetic recording medium, reading of the test pattern written to the first set of nonconsecutive data tracks, and identifying flaws within the first set of nonconsecutive data tracks and the second set of nonconsecutive data tracks based on the reading the test pattern.

Example systems, data storage devices, testers, and methods for storage device configuration using mutual information are described. A data storage device may include channel circuit configuration settings for the encoding and decoding of data written to a non-volatile storage medium. Mutual information metrics may be calculated based on a multi-bit symbol size to compensate for inter-symbol interference and compared to mutual information thresholds to determine the configuration settings, such as bit and track densities, error correction codes, and modulation codes. Mutual information metrics may be used to characterize heads and media independent of the configuration settings.

Example systems, data storage devices, testers, and methods for storage device configuration using symbol context mutual information are described. A data storage device may include channel circuit configuration settings for the encoding and decoding of data written to a non-volatile storage medium. The configuration settings may be determined by determining a known pattern for a sector, determining a series of symbol contexts, determining mutual information for each symbol context, and using the symbol context mutual information to determine relationships among configuration settings, such as bit size, error correction code rate, and modulation code. Once determined, the configuration settings may be used to configure the modulation code and ECC rate for the channel circuit of the data storage device.

According to one embodiment, a magnetic disk device including a disk, a head configured to write write data to the disk, and a controller configured to write first data including a high-frequency pattern, detect, from a reproduced waveform obtained by reading the written first data, a difference between a first percentage by which high-frequency patterns of a first polarity are lost and a second percentage by which high-frequency patterns of a second polarity obtained by reversing the first polarity are lost, and adjust a high-frequency pattern of the first polarity of the write data or a high-frequency pattern of the second polarity of the write data on the basis of the difference.

The present invention provides a testing system for a video and audio reproduction system, the testing system comprising a data source, comprising video and audio data for reproduction by the video and audio reproduction system, the video and audio data comprising unique marks in every video frame and every audio frame, a recording unit, configured to record a video stream and an audio stream generated by the video and audio reproduction system based on the video and audio data, and a test processor, configured to extract the unique marks from the recorded video stream and the recorded audio stream, and to verify if respective unique marks of simultaneous video frames and audio frames have been recorded by the recording unit simultaneously. Furthermore, the present invention provides a testing method, a computer program product, and a non-transitory computer readable data carrier.

A method includes moving a heat-assisted magnetic recording head relative to a magnetic recording medium comprising a plurality of tracks, the head comprising a reader and a writer including a near-field transducer (NFT) optically coupled to a laser diode, the writer comprising a center which is laterally offset relative to a center of the reader to define a writer-reader offset (WRO) therebetween. Patterns are written to a particular track at a plurality of laser diode current levels. The patterns are read and a WRO value is calculated at a peak amplitude position for each of the laser diode current levels. A slope of the WRO values is determined with the laser current diode levels. A health condition of the NFT is determined by determining if the slope is greater than a predetermined threshold indicative of non-uniform activation across the NFT.

According to one embodiment, a magnetic recording and reproducing device includes a magnetic recording medium including a plurality of recording tracks, a magnetic head, and a controller. The plurality of recording tracks includes a first track. The controller causes the magnetic head to implement a first recording operation of recording first information in at least two of a plurality of first track recording components included in the first track. The controller causes the magnetic head to implement a first reproduction operation of reproducing the first information from a first information reproducing/recording component of one of the at least two of the plurality of first track recording components.

The present invention provides a testing system for a video and audio reproduction system, the testing system comprising a data source, comprising video and audio data for reproduction by the video and audio reproduction system, the video and audio data comprising unique marks in every video frame and every audio frame, a recording unit, configured to record a video stream and an audio stream generated by the video and audio reproduction system based on the video and audio data, and a test processor, configured to extract the unique marks from the recorded video stream and the recorded audio stream, and to verify if respective unique marks of simultaneous video frames and audio frames have been recorded by the recording unit simultaneously. Furthermore, the present invention provides a testing method, a computer program product, and a non-transitory computer readable data carrier.