According to the embodiment, an HDC receives a plurality of data segments from a host, and executes generation and addition of a first code and output of a data segment to which the first code is added to each data segment. An HDC calculates exclusive OR with respect to the first codes, and outputs obtained first information. The RWC performs data conversion and calculation of exclusive OR on the plurality of data segments to which the first code is added, and outputs the plurality of data segments after the data conversion and a track parity obtained by the calculation of the exclusive OR. The RWC acquires the first code from the plurality of data segments. The RWC calculates exclusive OR with respect to a group of the second codes which are the acquired first codes to acquire second information. The RWC compares the first information with the second information.

A heat-assisted magnetic recording head is moved relative to a magnetic recording medium. The medium comprises a plurality of sectors. The sectors define a plurality of sector groups distributed around a circumference of the medium. The sectors of each sector group are written using different operational currents supplied to a laser diode of the head such that at least one sector from each sector group is written using one of the different operational currents. For each of the different operational currents, an average write performance metric is calculated for all sectors written at each of the different operational currents. A particular operational current of the different operational currents is determined that results in a best average write performance metric.

A tape drive-implemented method, according to one embodiment, includes: causing a servo reader to move in a first direction over a high-density servo pattern which includes a plurality of high-density servo tracks. Each of the servo tracks includes at least two patterns written at different frequencies to produce different periodic waveforms during readback. Moreover, a readback signal is received from the servo reader as the servo reader moves in the first direction. The readback signal is used to set a gain parameter for each of the respective periodic waveforms. Other systems, methods, and computer program products are described in additional embodiments.

An apparatus according to one embodiment includes an array of 2N+1 transducers on a pitch, where at least one of the transducers within the array is configured as a servo reader. In addition, one of the transducers configured as the servo reader is flanked by transducers on each side.

An apparatus according to one embodiment includes an array of transducers, where the array of transducers includes at least one contiguous group of transducers in a number specified in a format and at least two servo readers, where the servo readers are symmetrically positioned about the contiguous group of transducers and the servo readers are asymmetrically positioned relative to a centerline of the array of transducers. Moreover, a number of transducers in the contiguous group of transducers is less than a number of transducers in the array of transducers.

Methods, apparatuses and systems for detecting defective sectors on a recording medium. A defective sector detector apparatus comprises an error-corrected ECC symbol number calculator and a defective sector determination unit. The error-corrected ECC symbol number calculator is configured to count a total number of error correcting code (ECC) symbols that are error-corrected in data read from data sectors on a track of a recording medium of the storage device. The defective sector determination unit is configured to receive the total number of ECC symbols that are error-corrected for a data sector from the error-corrected ECC symbol number calculator and determine whether the total number of ECC symbols that are error-corrected exceeds a threshold value. If it is determined that the total number of ECC symbols that are error-corrected exceeds the threshold value, the defective sector determination unit outputs information indicating the data sector to be a defective sector.

A shingled magnetic recording (SMR) hard disk drive (HDD) is configured with a multi-level cache. To expedite execution of read commands, the SMR HDD is configured to generate and store a Bloom filter in a memory that can be quickly accessed by the drive controller whenever data are stored in certain levels of the multi-level cache. When data are flushed from one level of media cache to an SMR band included in a lower level of media cache, a Bloom filter is generated based on the logical block addresses (LBAs) stored in that SMR band. Thus, when the SMR HDD receives a read command for data that are associated with a particular LBA and are stored in an SMR region of the HDD, the drive controller can query the Bloom filter for each different SMR region of the HDD in which data for that LBA can possibly be stored.

A shingled magnetic recording (SMR) hard disk drive (HDD) receives a read command for data associated with a range of logical block addresses (LBAs). In situations where a first portion of valid data associated with the range of LBAs is stored in an SMR region of the HDD and a second portion of valid data associated with the range of LBAs is stored in a non-SMR region of the HDD, the first portion is read from the SMR region in a single disk access and copied to a first buffer of the HDD, and the second portion is read from the non-SMR region in one or more disk accesses and copied to a second buffer of the HDD. The valid data associated with the range of LBAs stored in the second buffer are copied to the first buffer to be combined with valid data associated with the range of LBAs stored in the first buffer, and the combined valid data is then transferred to the host to complete execution of the read command.

A storage system includes a final level cache (FLC) module coupled to a storage medium. The storage medium includes a bulk storage portion having a higher data density than a cache storage portion. The cache storage portion is configured as an FLC cache accessed by the FLC module prior to accessing the bulk storage portion. The FLC module receives a request for data from a processor coupled to one or more levels of cache that are separate from the FLC cache. The processor generates the request if the data is not cached in the one or more levels of cache. The FLC module determines whether the data requested is cached in the FLC cache, retrieves the data from the FLC cache if the data is cached in the FLC cache, and retrieves the data from the bulk storage portion if the data is not cached in the FLC cache.

A plurality of kinds of LPCM signals/compression digital audio signals is switched to one another in transmission, thereby enabling audio reproduction to be satisfactorily carried out. A digital audio signal is transmitted to an external apparatus through a predetermined transmission path. Information associated with the digital audio signal to be next transmitted is added to the digital audio signal which is currently being transmitted. For example, first metadata exhibiting a transmission frequency of the digital audio signal, and second metadata exhibiting a data type of the digital audio signal are contained in the information.