According to one embodiment, a first decoding circuit calculates likelihood information by executing Viterbi decoding using a parameter for normalizing a branch metric on a signal sequence read from a magnetic disk. The second decoding circuit generates a first bit data sequence by iterative decoding using the likelihood information, and executes a check using a parity check matrix on the first bit data sequence. The control circuit causes the first decoding circuit and the second decoding circuit to repeatedly execute decoding, and updates the parameter in accordance with a check result obtained every time the decoding by the first decoding circuit and the second decoding circuit is executed. An acquisition circuit acquires numerical information corresponding to the number of bit errors included in the first bit data sequence obtained when the number of times of executions of the decoding is equal to a first value.

A data storage device includes a flash memory and a controller. The flash memory includes a plurality of dies, and each of the dies includes a first memory plane and a second memory plane, wherein each of the first memory plane and the second memory plane includes a plurality of physical pages. The controller retrieves data of a first physical page of the first memory plane and data of a second physical page of the second memory plane in response to a read command which is arranged to read a target page.

The present disclosure describes aspects of codeword interleaving for magnetic storage media. In some aspects, segments of a codeword are spread or interleaved across multiple sectors of magnetic storage media. Data for one or more codewords may be received by a read channel and, for each codeword, a respective indicator is selected or received. The indicator may indicate which partitions of the multiple sectors that segments of one of the codewords are to be written. The data is then encoded to provide the codewords and segments of the codewords are placed in an interleaver based on the respective indicator corresponding to the codeword. The codeword segments are written from the interleaver to partitions of the multiple sectors of the magnetic storage media. By so doing, codewords may be spread across multiple sectors, such that a loss of a few sectors does not prevent readback and decoding of the codewords.

A data storage device is disclosed comprising a head actuated over a disk. A first plurality of codewords and corresponding parity sector are generated, and a second plurality of codewords and corresponding parity sector are generated. The first and second plurality of codewords are written to the disk, and during a read of the first and second set of codewords, M codeword locations within the data track that are unrecoverable are saved, and N codeword locations out of the M codeword locations are selected based on a quality metric of the read. The N codewords are reread from the data track at the N codeword locations and reliability metrics associated with the N codewords are saved. The saved reliability metrics are updated using at least one of the first parity sector or the second parity sector.

A cartridge memory used for a tape cartridge includes: a communication unit that communicates with a recording and reproducing device using a wireless communication method defined by an ISO 14443-2 standard which is a wireless communication standard; a non-volatile memory with a storage capacity exceeding 16 KB; and a control unit that writes or reads data to or from the non-volatile memory on a word-by-word basis (2 bytes at a time) or on a block-by-block basis (32 bytes at a time). The non-volatile memory includes a plurality of memory banks each having a storage capacity of 128 KB or less. The control unit writes or reads data defined by a magnetic tape standard to or from one or two or more first memory banks among the plurality of the memory banks, and writes or reads additional data to or from one or two or more second memory banks other than the first memory bank.

A dynamic scalable error correction coding (ECC) scheme for a data storage system involves a system controller predicting a type and/or amount of ECC needed to reconstruct data to be stored on a particular data storage device(s) based on operational data integrity information accessed from the array of data storage devices. Thus, redundancy does not need to be allocated unless required. The devices may be logically grouped into subsets according to common characteristics, whereby the prediction made for a device in a subset may be based on the data integrity information from that subset, as well as from other relevant subsets.

A method includes storing a superset of data on a data storage medium along with a corresponding superset superparity. The superset of data includes multiple sets of data, and the corresponding superset superparity is calculated based on all of the multiple sets of data. The method also includes updating at least one subset of the superset of data. The subset has a subset superparity. The superset superparity is updated with the subset superparity, and the subset superparity and a location of the subset within the superset are employed to carry out error correction operations.

A system is provided to receive a first request to write data to a hard disk drive (HDD) which comprises a plurality of tracks which can be configured as a conventional magnetic recording (CMR) media or as a shingled magnetic recording (SMR) media, wherein an SMR-configured track stores a greater amount of data than a CMR-configured track. The system writes the data to a first CMR-configured track, and classifies data stored in CMR-configured tracks as hot or cold based on a first or a second predetermined threshold. The system copies cold data from the CMR-configured tracks to an SMR zone, and makes available portions of the CMR-configured tracks previously occupied by the cold data.

A method includes storing a superset of data on a data storage medium along with a corresponding superset superparity. The superset of data includes multiple sets of data, and the corresponding superset superparity is calculated based on all of the multiple sets of data. The method also includes updating at least one subset of the superset of data. The subset has a subset superparity. The superset superparity is updated with the subset superparity, and the subset superparity and a location of the subset within the superset are employed to carry out error correction operations.

A data coding device includes an error correction coder that converts user data into ECC data by error correction coding, a modulation coder that converts the ECC data into a series of modulated code data, a detector that detects a local concentration of modulation marks/modulation spaces that are shorter than or equal to a prescribed minimum run-length plus N from the series of modulated code data, a conversion determiner that judges whether to convert the series of modulated code data into another series of modulated code data, according to a concentration, detected by the detector, of the modulation marks/modulation spaces, and a modulation data converter that converts the series of modulated code data into the another series of modulated code data.