Abstract: In one implementation, the disclosure provides a system including a detector configured to generate an output of a first log-likelihood ratio for each bit in an input data stream. The system also includes at least one look-up table providing a mapping of the first log-likelihood ratio to a second log-likelihood ratio. The mapping between the first log-likelihood ratio and the second log-likelihood ratio is non-linear. The system also includes a decoder configured to generate an output data stream using the second log-likelihood ratio to generate a value for each bit in the input data stream.

Abstract: Embodiments herein provide for a controller that is operable to soft read a data bit a plurality of times, to generate a bit set for the data bit from the soft reads, to logically operate on the bit set, and to generate a Hamming weight for the data bit based on the logical operation. The Hamming weight has fewer bits than the bit set and is operable to correct the data bit.

Abstract: Systems and methods are disclosed for open block stability scanning. When a solid state memory block remains in an open state, where the block is only partially filled with written data, for a prolonged period of time, a circuit may perform a scan on the block to determine the stability of the stored data. When the scan indicates that the data is below a stability threshold, the data may be refreshed by reading the data and writing it to a new location. When the scan indicates that the data is above a stability threshold, the circuit may extend the time period in which the block may remain in the open state.

Abstract: Systems and methods are disclosed for implementing sector management in drives having multiple modulation coding. A circuit may be configured to generate a data sector having a first number of bits based on a first modulation encoding scheme associated with a first location of a data storage medium, determine a difference between the first number of bits and a second number of bits corresponding to a second modulation encoding scheme associated with a second location of the data storage medium, append a number of padding bits to the data sector based on the difference, and store the data sector to the second location of the data storage medium. The data sector may be a sector reallocated from the first location to the second location. The data sector may also be an intermediate parity sector stored to a media cache region of the data storage device.

Abstract: Page-level reference voltage parameterization techniques are provided for solid state memory devices. A method comprises obtaining a bit error count for a plurality of page numbers across a plurality of blocks of a solid state memory device; determining a substantially optimal reference voltage for each page number that substantially minimizes a corresponding bit error count; collecting, for each reference voltage, page numbers and corresponding substantially optimal reference voltages; and determining, for each reference voltage, a non-linear function that substantially fits a distribution of the collected page numbers and corresponding substantially optimal reference voltages, wherein a given page having a given page number is read using a plurality of parameters of the non-linear function to generate the substantially optimal reference voltage for the given page number.

Abstract: Systems and methods presented herein provide for monitoring block, page, and/or stripe degradation. In one embodiment, a controller is operable to scan a first block of memory to identify a failure in a portion of the first block. The controller suspends input/output (I/O) operations to the failed portion of the first block, and tests the failed portion of the first block to determine if the failure is a transient failure. Testing includes loading the portion of the first block with data, and reading the data from the loaded portion of the first block. If the failure subsides after testing, the controller is further operable to determine that the failure is a transient failure, and to resume I/O operations to the portion of the first block.

Abstract: Systems and methods are disclosed for employing variable amounts of parity sectors. In certain embodiments, an apparatus may comprise a processor configured to generate a first number of parity sectors for write data to be written to a nonvolatile memory, and store the write data and a second number of parity sectors to the nonvolatile memory, the second number of parity sectors being a subset less than all of the first number of parity sectors. The processor may further select additional parity sectors from the first number of parity sectors based on error metrics for the write data, store the additional parity sectors to the nonvolatile memory, and perform error recovery on the write data based on the additional parity sectors.

Abstract: Embodiments herein provide for a controller that is operable to soft read a data bit a plurality of times, to generate a bit set for the data bit from the soft reads, to logically operate on the bit set, and to generate a Hamming weight for the data bit based on the logical operation. The Hamming weight has fewer bits than the bit set and is operable to correct the data bit.

Abstract: Systems and methods are disclosed for minimizing reads for reallocated sectors of a data storage medium. An apparatus may be configured to selectively skip over reallocated sectors in an LBA range without interrupting a read, via generating a skip mask or by beginning the read after the reallocated sector and reading the entire track up to the reallocated sector. When a number of sectors not read from the LBA range during the read operation is less than an amount of sectors that can be recovered based on an error correction capability, the data of the reallocated sector may be reconstructed using error correction data rather than by performing a read at the reallocated sector.

Abstract: An apparatus may include a circuit that initializes a read operation to read one or more requested data segments of a respective data unit. The circuit may generate equalized combined samples for a failed data segment of the one or more requested data segments based on first samples and second samples. In addition, the circuit may perform iterative outer code recovery for the data unit utilizing the equalized combined samples as samples for the failed data segment.

Abstract: Systems and methods are disclosed for wear-based access optimization. An apparatus may comprise a circuit configured to perform a data access operation at a target location of a memory, and determine a wear value of the target location. The circuit may compare the wear value to global wear value of other locations of the drive, and adjust data access parameters for the target location based on the comparison.

Abstract: Method and apparatus for decoding data. In some embodiments, an LDPC decoder has a variable node circuit (VNC) with a plurality of variable nodes configured to store bit reliability values of m-bit code bits. A check node circuit (CNC) has a plurality of check nodes configured to perform parity check operations upon n-bit messages from the VNC. Each n-bit message is formed from a combination of the bit reliability values and stored messages from the check nodes. A pre-saturation compensation circuit is configured to maintain a magnitude of each n-bit message received by the CNC below a saturation limit comprising the maximum value that can be expressed using p bits, with p less than n and each of the n-bit messages received by the CNC having a different magnitude. The pre-saturation compensation circuit may apply different scaling and/or bias factors to the n-bit messages over different decoding iterations.

Abstract: Systems and methods for improving data refresh in flash memory are described. In one embodiment, the method includes identifying a first garbage collection unit (GCU) of the storage system, computing a parity function in relation to the first GCU, identifying a data impairment in a first block, the first block being from the N blocks in the first GCU, removing the first block from the first GCU after identifying the data impairment in the first block, and recomputing the parity function when the first block is not cloned.

Abstract: An apparatus may include a circuit that performs one or more read and recovery operations for one or more data segments including updating an outer code syndrome for one or more recovered data segments recovered by the one or more read and recovery operations and preventing updates of the outer code syndrome for one or more failed data segments not recovered by the one or more read and recovery operations.

Abstract: Embodiments herein provide for a controller that is operable to soft read a data bit a plurality of times, to generate a bit set for the data bit from the soft reads, to logically operate on the bit set, and to generate a Hamming weight for the data bit based on the logical operation. The Hamming weight has fewer bits than the bit set and is operable to correct the data bit.

Abstract: Systems and methods presented herein provide for monitoring block, page, and/or stripe degradation. In one embodiment, a controller is operable to scan a first block of memory to identify a failure in a portion of the first block. The controller suspends input/output (I/O) operations to the failed portion of the first block, and tests the failed portion of the first block to determine if the failure is a transient failure. Testing includes loading the portion of the first block with data, and reading the data from the loaded portion of the first block. If the failure subsides after testing, the controller is further operable to determine that the failure is a transient failure, and to resume I/O operations to the portion of the first block.

Abstract: Systems and methods are disclosed for performing segment-based outer code recovery at a data storage device. An apparatus may comprise a circuit configured to disable outer code error recovery, and perform a read operation spanning a plurality of segments of a data storage medium, a segment including a plurality of sectors. The circuit may identify one or more segments from the plurality of segments that have one or more sectors with an error. For an identified segment of the one or more segments, the circuit may perform a re-read operation with outer code error recovery enabled, and perform outer code recovery on sectors with an error within the identified segment.

Abstract: Method and apparatus for decoding data. In some embodiments, an LDPC decoder has a variable node circuit (VNC) with a plurality of variable nodes configured to store bit reliability values of m-bit code bits. A check node circuit (CNC) has a plurality of check nodes configured to perform parity check operations upon n-bit messages from the VNC. Each n-bit message is formed from a combination of the bit reliability values and stored messages from the check nodes. A pre-saturation compensation circuit is configured to maintain a magnitude of each n-bit message received by the CNC below a saturation limit comprising the maximum value that can be expressed using p bits, with p less than n and each of the n-bit messages received by the CNC having a different magnitude. The pre-saturation compensation circuit may apply different scaling and/or bias factors to the n-bit messages over different decoding iterations.

Abstract: Systems and methods are disclosed for open block management. In certain embodiments, an apparatus may comprise a circuit configured to determine an error sensitivity of a last-written page of a block of a solid state memory that is in an open state where the block has not been fully filled with data. The error sensitivity may include a value that represents a susceptibility to developing data errors while in the open state. The circuit may perform a first error mitigation procedure when the error sensitivity is lower than a first threshold, include increasing an open block timeout period applied to the last-written page. The circuit may perform a second error mitigation procedure when the error sensitivity is higher than the first threshold, including copying data from the block to a new location when a first open block timeout is reached.

Abstract: Systems and methods are disclosed for open block refresh management. In certain embodiments, an apparatus may comprise a circuit configured to monitor an amount of time a block of a solid-state memory remains in an open state where the block has not been fully filled with data, and in response to reaching an open block time limit, compare an amount of the block already written with data against a threshold amount. When less than a threshold amount of the block has been written with data, the circuit may refresh data from a last N pages from the block by writing the data to a new location, N being a number of pages less than all pages in the block. When more than the threshold amount of the block has been written with data, the circuit may fill a remaining unwritten amount of the block with dummy data.