A method for performing error correction for a plurality of storage drives and a storage appliance comprising a plurality of storage devices is disclosed. In one embodiment, the method includes generating a first set of parity bits from a first set of data of at least one of the plurality of storage devices, the first set of parity bits capable of correcting a first number of error bits of the first set of data. The method further includes generating a second set of parity bits from a concatenated set of the first data and a second set of data from at least another of the plurality of storage devices, the second set of parity bits capable of correcting a second number of error bits of the first set of data, the second number being greater than the first number. The method further includes reading the first set of data and (i) correcting error bits within the first set of data with the first set of parity bits where a number of error bits is less than the first number of error bits; and (ii) correcting error bits within the first set of data with the second set of parity bits where the number of error bits is greater than the first number.

A memory device having a Low-Density Parity-Check (LDPC) decoder that is energy efficient and has a low error floor. The decoder is configured to determine syndromes of bits in a codeword, select bits in the codeword based at least in part on the syndromes according to a first mode, and flip the selected bits in the codeword. The decoder can repeat the bit selection and flipping operations to iteratively improve the codeword and reduce parity violations. Further, the decoder can detect a pattern in parity violations of the codeword in its iterative bit flipping operations. In response, the decoder can change from the first mode to a second mode in bit selection for flipping. For example, the decoder can transmit from a dynamic syndrome mode to a static syndrome mode in response to the pattern of repeating a cycle of bit flipping iterations.

Methods, systems, and devices for memory error correction based on layered error detection are described. In some examples, a memory system identifies, based on a first type of error detection procedure, that a set of bits includes a quantity of erroneous bits that is uncorrectable based on the first type of error detection procedure alone. The memory system generates one or more candidate sets of bits based on altering different groups of bits within the set of bits and evaluate one or more such candidate sets of bits using a second type of error detection procedure until a candidate set of bits is identified as error-free. The memory system then corrects the set of bits based on the candidate set of bits identified as error-free.

Devices and techniques for extended error correction in a storage device are described herein. A first set of data, that has a corresponding logical address and physical address, is received. A second set of data can be selected based on the logical address. Secondary error correction data can be computed from the first set of data and the second set of data. Primary error correction data can be differentiated from the secondary error correction data by being computed from the first set of data and a third set of data. The third set of data can be selected based on the physical address of the first set of data. The secondary error correction data can be written to the storage device based on the logical address.

Devices, systems and methods for improving reliability and security of a memory system are described. An example method includes receiving a seed value and a data stream, generating, based on the seed and using a physical unclonable function (PUF) generator, a PUF data pattern, generating, based on the seed, a pseudo-random data pattern, performing a first logic operation on the PUF data pattern and the data stream to generate a result of the first logic operation as a first data sequence, and performing a second logic operation on the pseudo-random data pattern and a second data sequence that is based on the first data sequence to generate a result of the second logic operation as a third data sequence for storage on the memory system, wherein the PUF generator is selected at least in-part based on one or more physical characteristics of the memory system.

Example systems, read channel circuits, data storage devices, and methods to provide signal correction based on soft information in a read channel are described. The read channel circuit includes a soft output detector, such as a soft output Viterbi algorithm (SOVA) detector, and a signal correction circuit. The soft output detector passes detected data bits and corresponding soft information to the signal correction circuit. The signal correction circuit uses the soft information to determine a signal correction value, which is combined with input signal to return a corrected signal to the soft output detector for a next iteration. In some configurations, the signal correction value may compensate for DC offset, AC coupling poles, and/or signal asymmetries to reduce baseline wander in the read channel.

A method of screening weak bits in a memory array includes dividing the memory array into a first and a second memory array, storing a first set of data in the first memory array, performing a first baking process on the first memory array or applying a first magnetic field to the first memory array, determining that a first portion of the first set of data stored in the first memory array is altered by the first baking process or the first magnetic field, and at least one of replacing memory cells of a first set of memory cells that are storing the first portion of the first set of data with corresponding memory cells in the second memory array of the memory array, or not using the memory cells of the first set of memory cells storing the first portion of the first set of data.

An apparatus and method for generating a broadcast signal frame corresponding to a time interleaver supporting a plurality of operation modes are disclosed. An apparatus for generating broadcast signal frame according to an embodiment of the present invention includes a combiner configured to generate a multiplexed signal by combining a core layer signal and an enhanced layer signal at different power levels; a power normalizer configured to reduce the power of the multiplexed signal to a power level corresponding to the core layer signal; a time interleaver configured to generate a time-interleaved signal by performing interleaving that is applied to both the core layer signal and the enhanced layer signal; and a frame builder configured to generate a broadcast signal frame including a preamble for signaling time interleaver information corresponding to the time interleaver, the time interleaver uses one of time interleaver groups, and the time interleaver performs the interleaving by using one of a plurality of operation modes.

A method includes identifying an independent data object of a plurality of independent data objects for retrieval from dispersed storage network (DSN) memory. The method further includes determining a mapping of the plurality of independent data objects into a data matrix, wherein the mapping is in accordance with the dispersed storage error encoding function. The method further includes identifying, based on the mapping, an encoded data slice of the set of encoded data slices corresponding to the independent data object. The method further includes sending a retrieval request to a storage unit of the DSN memory regarding the encoded data slice. When the encoded data slice is received, the method further includes decoding the encoding data slice in accordance with the dispersed storage error encoding function and the mapping to reproduce the independent data object.

According to one embodiment, a memory system includes a nonvolatile memory and a controller which controls the nonvolatile memory. The controller notifies to an outside an extensive signal which indicates a predetermined state of the nonvolatile memory or the controller.