Abstract: Low-density parity-check (LDPC) coding based on memory cell voltage distribution (CVD) in data storage devices. In one embodiment, a memory controller includes a memory interface configured to interface with a non-volatile memory; and a controller. The controller is configured to receive a plurality of data pages to be stored in the non-volatile memory, and transform the plurality of data pages into a plurality of transformed data pages. The controller is further configured to determine a plurality of parity bits based on the plurality of transformed data pages, and store the plurality of data pages and the plurality of parity bits in the non-volatile memory.

Abstract: A storage system has a memory with memory cells that can store a non-power-of-two number of states. A map is used to distribute data bits in the memory. The map can be a modified version of a quadrature amplitude modulation (QAM) map. The mapping can be done by a controller in the storage system or by the memory die. Performing the mapping in the memory die can reduce data traffic between the controller and the memory die, which can provide an improvement to performance and power consumption.

Abstract: A data storage device includes a memory device including a plurality of endurance groups and a controller coupled to the memory device. The controller is configured to allocate tokens to the plurality of endurance groups, determine whether endurance group has sufficient tokens to perform an operation, and either deny the operation or approve the operation. The operation is selected from the group consisting of: garbage collection, relocation of data, and read scrubbing. Each operation has the same or different cost as another operation. The controller is further configured to set thresholds for each endurance group of the plurality of endurance groups and adjust a threshold for one or more endurance groups of the plurality of endurance groups. The controller is further configured to determine whether the operation will breach quality of service for other endurance groups.

Abstract: Interleaved ECC coding for key-value data storage devices. In one embodiment, a controller includes a memory interface including a namespace database; an ECC engine; a controller memory; and an electronic processor. The electronic processor is configured to receive a host write command, determine whether write access was setup as a key-value (KV) namespace in the namespace database and is associated with the host write command, and control the ECC engine and the memory interface to perform one or more program operations on the data in the memory using the interleaved ECC coding and based on the host write command in response to determining that the write access was setup as the KV namespace in the namespace database and the KV namespace is associated with the host write command.

Abstract: A data storage device includes a memory device including a plurality of endurance groups and a controller coupled to the memory device. The controller is configured to allocate tokens to the plurality of endurance groups, determine whether endurance group has sufficient tokens to perform an operation, and either deny the operation or approve the operation. The operation is selected from the group consisting of: garbage collection, relocation of data, and read scrubbing. Each operation has the same or different cost as another operation. The controller is further configured to set thresholds for each endurance group of the plurality of endurance groups and adjust a threshold for one or more endurance groups of the plurality of endurance groups. The controller is further configured to determine whether the operation will breach quality of service for other endurance groups.

Abstract: A storage system and method for implementing an encoder, decoder, and/or buffer using a field programmable gate array are provided. In one embodiment, a storage system is provided with a field programmable gate array and a memory that stores sets of instruction code for the field programmable gate array. The sets of instruction code can be for different error decoder implementations, for providing an additional encoder and/or decoder, or for implementing a host memory buffer or a controller memory buffer.

Abstract: A method and apparatus for determining the sector size and concomitant host metadata size to determine the difference between total size of the data block to be stored, and using the difference for parity data. This allows an increase in parity bits available for smaller sector sizes and/or data with smaller host metadata sizes. Because the amount of space available for additional parity bits is known, data with lower numbers of parity bits may be assigned to higher quality portions a memory array written with longer programming trim times, and/or written to memory dies with good redundant columns, further increasing performance and reliability.

Abstract: A data storage device includes a memory device having a plurality of endurance groups and a controller coupled to the memory device. The controller includes at least one decoder or at least one decoder group. The controller is configured to allocate a plurality of tokens to each endurance group of the plurality of endurance groups, receive a payment of tokens from an endurance group to access the at least one decoder or the at least one decoder group, and grant access to the at least one decoder or the at least one decoder group to the endurance group based on the payment of tokens. Each decoder or each decoder group is associated with the same or different payment of tokens and each endurance group has a maximum capacity of tokens.

Abstract: Calibration of soft bit reference levels in a non-volatile memory system is disclosed. When the soft bit reference levels are to be calibrated, encoded data is read from a group of the memory cells. The encoded data is decoded and error corrected. Therefore, the original data that was programmed into the memory cells is recovered. The group of memory cells are sensed at candidate soft bit reference levels, and possibly other reference levels. For each candidate soft bit reference level, mutual information between the original programmed data and the data for that candidate soft bit reference level is determined. The mutual information serves as a good measure for how well the candidate soft bit reference level will aid in decoding the data. In an aspect, a soft bit reference level having the highest mutual information out of several candidates is selected as the calibrated soft bit reference level.

Abstract: A method and apparatus for content aware decoding utilizes a pool of decoders shared data statistics. Each decoder generates statistical data of content it decodes and provides these statistics to a joint statistics pool. As codewords arrive at the decoder pool, the joint statistics are utilized to estimate or predict any corrupted or missing bit values. Codewords may be assigned to a specific decoder, such as a tier 1 decoder, a tier 2 decoder, or a tier 3 decoder, based on a syndrome weight or a bit error rate. The assigned decoder updates the joint statistics pool after processing the codeword. In some embodiments, each decoder may additionally maintain local statistics regarding codewords, and use the local statistics when there is a statistically significant mismatch between the local statistics and the joint statistics pool.

Abstract: Calibration of soft bit reference levels in a non-volatile memory system is disclosed. When the soft bit reference levels are to be calibrated, encoded data is read from a group of the memory cells. The encoded data is decoded and error corrected. Therefore, the original data that was programmed into the memory cells is recovered. The group of memory cells are sensed at candidate soft bit reference levels, and possibly other reference levels. For each candidate soft bit reference level, mutual information between the original programmed data and the data for that candidate soft bit reference level is determined. The mutual information serves as a good measure for how well the candidate soft bit reference level will aid in decoding the data. In an aspect, a soft bit reference level having the highest mutual information out of several candidates is selected as the calibrated soft bit reference level.

Abstract: A storage circuit is configured to store multiple vectors associated with variable and check nodes of an iterative decoding operation. As part of the iterative decoding operation, a processor circuit is configured to retrieve, from the storage circuit, an intermediate value vector, a first estimation vector, a second estimation vector, and a sign vector, and determine an absolute value of the intermediate value vector. The processor circuit is also configured, using the retrieved vectors, to generate updated values for the first and second estimation vectors as part of determining a bit estimate for a check node included in the iterative decoding operation.

Abstract: A data storage device includes a memory device and a controller coupled to the memory device. The controller is configured to create a dual parity matrix. The dual parity matrix includes a full parity form that includes a payload, a first parity portion, and a second parity portion and a reduced parity form that includes the payload and the first parity portion. The second parity portion is 0. The controller is further configured to create an incremental parity construction matrix. The incremental parity construction matrix includes two arrays. A first array includes a first payload portion, a first, first parity portion, and a first, second parity portion and a second array includes a second payload portion, a second, first parity portion, and a second, second parity portion. The incremental parity construction matrix is arranged in either a block triangular construction or a block diagonal construction.

Abstract: Methods and apparatus are disclosed for managing the storage of dynamic neural network data within bit-addressable memory devices, such phase change memory (PCM) arrays or other storage class memory (SCM) arrays. In some examples, a storage controller determines an expected amount of change within data to be updated. If the amount is below a threshold, an In-place Write is performed using bit-addressable writes via individual SET and RESET pulses. Otherwise, a modify version of an In-place Write is performed where a SET pulse is applied to preset a portion of memory to a SET state so that individual bit-addressable writes then may be performed using only RESET pulses to encode the updated data. In other examples, a storage controller separately manages static and dynamic neural network data by storing the static data in a NAND-based memory array and instead storing the dynamic data in a SCM array.

Abstract: A memory controller includes, in one embodiment, a memory interface, a plurality of decoders, and a controller circuit. The memory interface is configured to interface with a memory having a plurality of wordlines. Each decoder of the plurality of decoders is configured to determine a bit error rate (BER). The controller circuit configured to generate a plurality of bit-error-rate estimation scan (BES) hypotheses for one wordline of the plurality of wordlines, divide the plurality of BES hypotheses among the plurality of decoders, receive BER results from the plurality of decoders based on the plurality of BES hypotheses, and adjust one or more read locations of the one wordline based on the BER results from the plurality of decoders.

Abstract: A method of temperature compensation to read a flash memory device includes determining a state of the flash memory device. An action is selected with a maximum Q-value from a Q-table for the current state during exploitation. A read operation of a code word from the flash memory device is conducted using one or more parameters according to the selected action. The code word is decoded with an error correction code (ECC) process.

Abstract: A read threshold voltage can vary over time due to process variation, data retention issues, and program disturb conditions. A storage system can calibrate the read threshold voltage using data from a decoded codeword read from a wordline in the memory. For example, the storage system can use the data instead of syndrome weight in a bit error rate estimate scan (BES). As another example, the storage system can use the data to generate a bit error rate distribution, which can be used instead of a cell voltage distribution histogram. Using these techniques can help reduce latency and power consumption, increase throughput, and improve quality of service.

Abstract: A storage system generates a low-density parity check (LDPC) code from a plurality of subcodes. The storage system stores each subcode in a different page of a word line in the memory. The subcode can be stored in one plane in the memory or across multiple planes. When the subcodes are stored across multiple planes, they can be stored in a checkboard pattern.

Abstract: A memory controller including, in one implementation, a memory interface and a control circuit. The memory interface is configured to receive a punctured codeword read from a non-volatile memory. The control circuit is configured to determine error probability values for a plurality of check nodes associated with a punctured bit included in the punctured codeword. The control circuit is also configured to determine an error probability value for the punctured bit based on the error probability values for the plurality of check nodes associated with the punctured bit and a variable degree associated with the punctured bit. The control circuit is further configured to determine a log likelihood ratio (LLR) value for the punctured bit based on the error probability value for the punctured bit. The control circuit is also configured to decode the punctured codeword using the LLR value for the punctured bit.

Abstract: A memory includes, in one embodiment, NAND elements; read/write circuitry; and compressed soft-bit circuitry. The compressed soft-bit circuitry is configured to determine or receive one or more NAND conditions and then determine a soft-bit delta and select a compression scheme based on the NAND conditions. The read/write circuitry is configured to read a set of hard bits from the NAND elements and sense a first set of soft-bits using the determined soft-bit delta while reading the set of hard bits from the NAND elements. The first set of soft-bits has a first fixed size, and each soft-bit of the first set of soft-bits indicates a reliability of a corresponding hard bit of the set of hard bits. The compressed soft-bit circuitry is also configured to generate a second set of soft-bits based on the selected compression scheme and output the second set of soft-bits to a controller.