Disclosed embodiments include an electronic device having a write-once memory (WOM) and a memory controller. The memory controller includes a host interface receiving a data word including first and second symbols, each having at least two bits, a WOM controller that encodes the first and second symbols and outputs a WOM-encoded word including first and second WOM codes corresponding to the first and second symbols, respectively, an error correction code (ECC) controller that encodes the WOM-encoded word and outputs an ECC-encoded word including the first and second WOM codes and a first set of ECC bits corresponding to a first write operation, and a memory device interface that writes the ECC-encoded word the WOM device in the first write operation. Each of the first and second WOM codes include at least three bits with at least two of the at least three bits having the same logic value.

Disclosed embodiments include an electronic device having a write-once memory (WOM) and a memory controller. The memory controller includes a host interface receiving a data word including first and second symbols, each having at least two bits, a WOM controller that encodes the first and second symbols and outputs a WOM-encoded word including first and second WOM codes corresponding to the first and second symbols, respectively, an error correction code (ECC) controller that encodes the WOM-encoded word and outputs an ECC-encoded word including the first and second WOM codes and a first set of ECC bits corresponding to a first write operation, and a memory device interface that writes the ECC-encoded word the WOM device in the first write operation. Each of the first and second WOM codes include at least three bits with at least two of the at least three bits having the same logic value.

A decoding method, a memory storage device, and a memory control circuit unit are provided. The decoding method includes: reading a codeword from a memory module and estimating error level information of the codeword; inputting the codeword and the error level information to an error checking and correcting circuit through a first message channel and a second message channel respectively; determining whether the error level information meets a default condition; if yes, inputting the codeword to a first decoding engine of the error checking and correcting circuit for decoding; otherwise, inputting the codeword to a second decoding engine of the error checking and correcting circuit for decoding, wherein a power consumption of the first decoding engine is lower than that of the second decoding engine, and a decoding success rate of the first decoding engine is lower than that of the second decoding engine. Therefore, an operating flexibility for decoding may be improved.

A decoding method, a memory storage device, and a memory control circuit unit are provided. The decoding method includes: reading a codeword from a memory module and estimating error level information of the codeword; inputting the codeword and the error level information to an error checking and correcting circuit through a first message channel and a second message channel respectively; determining whether the error level information meets a default condition; if yes, inputting the codeword to a first decoding engine of the error checking and correcting circuit for decoding; otherwise, inputting the codeword to a second decoding engine of the error checking and correcting circuit for decoding, wherein a power consumption of the first decoding engine is lower than that of the second decoding engine, and a decoding success rate of the first decoding engine is lower than that of the second decoding engine. Therefore, an operating flexibility for decoding may be improved.

Systems, apparatuses, and methods for transmission failure feedback associated with a memory device are described. A memory device may detect errors in received data and transmit an indication of the error when detected. The memory device may receive data and checksum information for the data from a controller. The memory device may generate a checksum for the received data and may detect transmission errors. The memory device may transmit an indication of detected errors to the controller, and the indication may be transmitted using a line that is different than an error detection code (EDC) line. A low-speed tracking clock signal may also be transmitted by the memory device over a line different than the EDC line. The memory device may transmit a generated checksum to the controller with a time offset applied to the checksum signaled over the EDC line.

One example of layer-by-layer error correction can include iteratively error correcting the codeword on a layer-by-layer basis with the first error correction circuit in a first mode and determining on the layer-by-layer basis whether a number of parity errors in a particular layer is less than a threshold number of parity errors. The codeword can be transferred to a second error correction circuit when the number of parity errors is less than the threshold number of parity errors. The codeword can be iteratively error corrected with the first error correction circuit in a second mode when the number of parity errors is at least the threshold number of parity errors. The threshold number of parity errors can be at least partially based on an adjustable code rate of the first error correction circuit or the second error correction circuit.

One example of layer-by-layer error correction can include iteratively error correcting the codeword on a layer-by-layer basis with the first error correction circuit in a first mode and determining on the layer-by-layer basis whether a number of parity errors in a particular layer is less than a threshold number of parity errors. The codeword can be transferred to a second error correction circuit when the number of parity errors is less than the threshold number of parity errors. The codeword can be iteratively error corrected with the first error correction circuit in a second mode when the number of parity errors is at least the threshold number of parity errors. The threshold number of parity errors can be at least partially based on an adjustable code rate of the first error correction circuit or the second error correction circuit.

Adaptive read threshold voltage tracking techniques are provided that employ bit error rate estimation based on a non-linear syndrome weight mapping. An exemplary device comprises a controller configured to determine a bit error rate for at least one of a plurality of read threshold voltages in a memory using a non-linear mapping of a syndrome weight to the bit error rate for the at least one of the plurality of read threshold voltages.

A determination that a first programming operation has been performed on a particular memory cell can be made. A determination can be made, based on one or more threshold criteria, whether the particular memory cell has transitioned from a state associated with a decreased error rate to another state associated with an increased error rate. In response to determining that the particular memory cell has transitioned from the state associated with the decreased error rate to the another state associated with the increased error rate, an operation can be performed on the particular memory cell to transition the particular memory cell from the another state associated with the increased error rate to the state associated with the decreased error rate.

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.