A data storage device can be tested while spinning at a variety of different speeds. Data may be written to a data sector with a transducing head while at least one disk of a data storage device spins about a spindle at a default speed. One or more tests can subsequently be executed on the disk by reading servo data stored on the disk while the disk spins at a test speed that is greater than the default speed.

Systems, methods, devices, circuits for data processing, and more particularly to systems and methods for data processing to identify a defect on a medium.

A method, apparatus, and system are provided for implementing in-situ monitoring of head overcoat burnishing and early detection of head failure in a hard disk drive (HDD). A voltage is applied across a slider-disk interface between the slider body and the disk. Realtime monitoring of electrical current flowing across the slider-disk interface is performed for determining an amount of burnishing of the slider.

A read channel module including an input, a location module and a generation module. The input is configured to receive a read-back signal from a rotating storage medium. The location module is configured to determine a location to insert a first imitation defect within the read-back signal. The first imitation defect imitates a first defect. The generation module is configured to (i) selectively generate the first imitation defect, and (ii) insert the first imitation defect in the read-back signal at the determined location.

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.

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.

According to one embodiment, a magnetic disk device includes a disk, a write head, a write processing unit, an error correction unit, a correction limit prediction unit, and a determination unit. During a write period in which the write processing is executed on the second data track, the correction limit prediction unit is capable of determining whether or not data of each of the target sectors of the first data track is damaged, and generates prediction information, and the determination unit determines whether or not to cause the write processing unit to continue the write processing on the second data track based on the prediction information.

According to one embodiment, a magnetic disk device includes a disk, a write head, a write processing unit, an error correction unit, a correction limit prediction unit, and a determination unit. During a write period in which the write processing is executed on the second data track, the correction limit prediction unit is capable of determining whether or not data of each of the target sectors of the first data track is damaged, and generates prediction information, and the determination unit determines whether or not to cause the write processing unit to continue the write processing on the second data track based on the prediction information.