Abstract: Devices, systems, and methods for improving operation of a memory device that uses a deep neural network (DNN), based on using non-uniform quantization for flexible power-of-two computations, are described. An example method includes receiving a plurality of initial weights of the DNN configured to determine a value of a read voltage associated with memory device, wherein the plurality of initial weights comprises at least one non-power-of-two quantized value or at least one floating point value. The method then aggregates the plurality of initial weights to generate a plurality of quantization functions, determines each of a plurality of quantized weights for a corresponding one of the plurality of quantization functions such that each of the plurality of quantized weights is a sum of powers-of-two, and configures the DNN to use the plurality of quantized weights to generate an updated value of the read voltage for retrieving information from the memory device.

Abstract: A method and a system for operating a deep neural network. In the method and system, a subset of floating-point values are used to represent weights in the DNN; the floating-point values are quantized onto a flexible-power-of-two (FPoT) alphabet; values in the FPoT alphabet are listed in a plurality of regions; and an empty region among the plurality of regions is merged to neighbour regions to output dusters of the weights in merged regions, the merged regions having respective centroids and boundary lines in between.

Abstract: Devices, systems, and methods for performance of an iterative decoder in a non-volatile memory are described. An example method includes receiving a noisy codeword that is based on a transmitted codeword generated from a low-density parity-check (LDPC) code, partitioning a maximum number of iterations of the iterative decoder into a plurality of stages, initializing a set of log likelihood ratios (LLRs) with symmetric LLRs, for each stage of the plurality of stages: performing a message passing algorithm, determining, at a last iteration of the current stage, a hard decision corresponding to a candidate version of the transmitted codeword, determining, based on the hard decision, a set of asymmetric LLRs, and assigning the set of asymmetric LLRs to the set of LLRs, and determining the candidate version of the transmitted codeword using the set of LLRs.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: Embodiments of the present disclosure provide a scheme for decoding over a small subgraph which highly likely includes some errors. A controller is configured to: control the first decoder to decode the data, read from the memory device, using a parity check matrix for the error correction code; extract one or more subgraphs from the entire bipartite graph of the parity check matrix, which is defined by a plurality of variable nodes and a plurality of check nodes when a particular condition satisfied; and control the second decoder to decode the decoding result of the first decoder using a submatrix of the parity check matrix corresponding to the extracted subgraphs.

Abstract: Devices, systems and methods for improving performance of a memory device are described. An example method includes receiving one or more parameters associated with a plurality of previous read operations on a page of the memory device, wherein the previous read operations are based on a plurality of read voltages, determining, using the one or more parameters as an input to a deep neural network comprising a plurality of layers, an updated plurality of read voltages, wherein each of the plurality of layers is a fully connected layer, and applying the updated plurality of read voltages to the memory device to retrieve information from the memory device, wherein the deep neural network uses a plurality of weights that have been processed using at least one of (a) a pruning operation, (b) a non-uniform quantization operation, or (c) a Huffman encoding operation.

Abstract: Devices, systems and methods for improving performance of a memory device are described. An example method includes receiving one or more parameters associated with a plurality of previous read operations on a page of the memory device, wherein the previous read operations are based on a plurality of read voltages, determining, using the one or more parameters as an input to a deep neural network comprising a plurality of layers, an updated plurality of read voltages, wherein each of the plurality of layers is a fully connected layer, and applying the updated plurality of read voltages to the memory device to retrieve information from the memory device, wherein the deep neural network uses a plurality of weights that have been processed using at least one of (a) a pruning operation, (b) a non-uniform quantization operation, or (c) a Huffman encoding operation.

Abstract: Embodiments of the present disclosure provide a scheme for decoding over a small subgraph which highly likely includes some errors. A controller is configured to: control the first decoder to decode the data, read from the memory device, using a parity check matrix for the error correction code; extract one or more subgraphs from the entire bipartite graph of the parity check matrix, which is defined by a plurality of variable nodes and a plurality of check nodes when a particular condition satisfied; and control the second decoder to decode the decoding result of the first decoder using a submatrix of the parity check matrix corresponding to the extracted subgraphs.

Abstract: After a predetermined period of time in a life cycle of a flash memory device, a plurality of reliability values corresponding to a plurality of reads of one or more of the plurality of memory cells are generated; each of the reads using a variation of a predetermined read level voltage. An offset voltage is then identified, offset from the read level voltage. The offset voltage corresponds to a zero crossing point in the range of the reliability values. Once the offset voltage is identified, the read level voltage is set to a calibrated voltage based on the offset voltage.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: After a predetermined period of time in a life cycle of a flash memory device, a plurality of reliability values corresponding to a plurality of reads of one or more of the plurality of memory cells are generated; each of the reads using a variation of a predetermined read level voltage. An offset voltage is then identified, offset from the read level voltage. The offset voltage corresponds to a zero crossing point in the range of the reliability values. Once the offset voltage is identified, the read level voltage is set to a calibrated voltage based on the offset voltage.

Abstract: After a predetermined period of time in a life cycle of a flash memory device, a plurality of reliability values corresponding to a plurality of reads of one or more of the plurality of memory cells are generated; each of the reads using a variation of a predetermined read level voltage. An offset voltage is then identified, offset from the read level voltage. The offset voltage corresponds to a zero crossing point in the range of the reliability values. Once the offset voltage is identified, the read level voltage is set to a calibrated voltage based on the offset voltage.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

Abstract: A plurality of flash memory wordlines of a flash storage device are divided into a plurality of wordline groups based on read error counts associated with the wordlines and a plurality of read level offsets. Each wordline group is associated with one of a plurality of read level offsets determined while dividing the plurality of flash memory wordlines, and associations between the plurality of read level offsets and the plurality of wordline groups are stored for use in connection with read levels to read the flash memory wordlines of the respective wordline groups.

Abstract: After a predetermined period of time in a life cycle of a flash memory device, a plurality of reliability values corresponding to a plurality of reads of one or more of the plurality of memory cells are generated; each of the reads using a variation of a predetermined read level voltage. An offset voltage is then identified, offset from the read level voltage. The offset voltage corresponds to a zero crossing point in the range of the reliability values. Once the offset voltage is identified, the read level voltage is set to a calibrated voltage based on the offset voltage.