Abstract: A method for data storage includes, in a memory that includes multiple memory blocks, specifying at a first time a first over-provisioning overhead, and storing data in the memory while retaining in the memory blocks memory areas, which do not hold valid data and whose aggregated size is at least commensurate with the specified first over-provisioning overhead. Portions of the data from one or more previously-programmed memory blocks containing one or more of the retained memory areas are compacted. At a second time subsequent to the first time, a second over-provisioning overhead, different from the first over-provisioning overhead, is specified, and data storage and data portion compaction is continued while complying with the second over-provisioning overhead.

Abstract: A decoding apparatus includes a decoder and a control unit. The decoder includes circuitry that is configured to decode an Error Correction Code (ECC) by operating in one of a first operational mode having a first power consumption, and a second operational mode, in which at least part of the circuitry that is active during the first operational mode is deactivated and which has a second power consumption that is lower than the first power consumption. The control unit is configured to evaluate a criterion with respect to an input code word, to select one of the first and second operational modes responsively to the criterion, and to invoke the decoder to decode the input code word using the selected operational mode.

Abstract: A method for operating a memory (36) includes storing data in a plurality of analog memory cells (40) that are fabricated on a first semiconductor die by writing input storage values to a group of the analog memory cells. After storing the data, multiple output storage values are read from each of the analog memory cells in the group using respective, different threshold sets of read thresholds, thus providing multiple output sets of the output storage values corresponding respectively to the threshold sets. The multiple output sets of the output storage values are preprocessed by circuitry (48) that is fabricated on the first semiconductor die, to produce preprocessed data. The preprocessed data is provided to a memory controller (28), which is fabricated on a second semiconductor die that is different from the first semiconductor die, so as to enable the memory controller to reconstruct the data responsively to the preprocessed data.

Abstract: A method includes accepting an input code word, which was produced by encoding data with an Error Correction Code (ECC), for decoding by a hardware-implemented ECC decoder. The input code word is pre-processed to produce a pre-processed code word, such that a first number of bit transitions that occur in the hardware-implemented ECC decoder while decoding the pre-processed code word is smaller than a second number of the bit transitions that would occur in the ECC decoder in decoding the input code word. The pre-processed code word is decoded using the ECC decoder, and the data is recovered from the decoded pre-processed code word.

Abstract: A method for data storage includes providing at least first and second readout configurations for reading storage values from analog memory cells, such that the first readout configuration reads the storage values with a first sense time and the second readout configuration reads the storage values with a second sense time, shorter than the first sense time. A condition is evaluated with respect to a read operation that is to be performed over a group of the memory cells. One of the first and second readout configurations is selected responsively to the evaluated condition. The storage values are read from the group of the memory cells using the selected readout configuration.

Abstract: A method for data readout includes sending to a memory device, which includes a plurality of analog memory cells, a request to read a requested memory page that is stored in a first group of the memory cells. A programming status of a second group of the memory cells is reported to the memory device, so as to cause the memory device to select a reading configuration responsively to the reported programming status and to read the requested memory page from the first group of the memory cells using the selected reading configuration. The requested memory page is received from the memory device.

Abstract: A method for data storage in a memory that includes multiple analog memory cells fabricated using respective physical media, includes identifying a group of the memory cells whose physical media have deteriorated over time below a given storage quality level. A rejuvenation process, which causes the physical media of the memory cells in the group to meet the given storage quality level, is applied to the identified group. Data is stored in the rejuvenated group of the memory cells.

Abstract: A method for operating a memory (28) that includes a plurality of analog memory cells (32) includes storing data in the memory by writing first storage values to the cells. Second storage values are read from the cells, and a Cumulative Distribution Function (CDF) of the second storage values is estimated. The estimated CDF is processed so as to compute one or more thresholds. A memory access operation is performed on the cells using the one or more thresholds.

Abstract: A method for data storage includes providing at least first and second readout configurations for reading storage values from analog memory cells, such that the first readout configuration reads the storage values with a first sense time and the second readout configuration reads the storage values with a second sense time, shorter than the first sense time. A condition is evaluated with respect to a read operation that is to be performed over a group of the memory cells. One of the first and second readout configurations is selected responsively to the evaluated condition. The storage values are read from the group of the memory cells using the selected readout configuration.

Abstract: A method for data storage includes storing data in a group of analog memory cells by writing respective storage values into the memory cells in the group. One or more of the memory cells in the group are read using a first readout operation that senses the memory cells with a first sense time. At least one of the memory cells in the group is read using a second readout operation that senses the memory cells with a second sense time, longer than the first sense time. The data stored in the group of memory cells is reconstructed based on readout results of the first and second readout operations.

Abstract: Methods for Error Correction Code (ECC) decoding include producing syndromes from a set of bits, which represent data that has been encoded with the ECC. An Error Locator Polynomial (ELP) is generated based on the syndromes. At least some of the ELP roots are identified, and the errors indicated by these roots are corrected. Each syndrome may be produced by applying to the bits vector operations in a vector space. Each syndrome is produced by applying vector operations using a different basis of the vector space. The ELP may be evaluated on a given field element by operating on ELP coefficients using serial multipliers, wherein each serial multiplier performs a sequence of multiplication cycles and produces an interim result in each cycle. Responsively to detecting at least one interim result indicating that the given element is not an ELP root, the multiplication cycles are terminated before completion of the sequence.

Abstract: Methods for Error Correction Code (ECC) decoding include producing syndromes from a set of bits, which represent data that has been encoded with the ECC. An Error Locator Polynomial (ELP) is generated based on the syndromes. At least some of the ELP roots are identified, and the errors indicated by these roots are corrected. Each syndrome may be produced by applying to the bits vector operations in a vector space. Each syndrome is produced by applying vector operations using a different basis of the vector space. The ELP may be evaluated on a given field element by operating on ELP coefficients using serial multipliers, wherein each serial multiplier performs a sequence of multiplication cycles and produces an interim result in each cycle. Responsively to detecting at least one interim result indicating that the given element is not an ELP root, the multiplication cycles are terminated before completion of the sequence.

Abstract: A method for data storage includes storing first data bits in a set of multi-bit analog memory cells at a first time by programming the memory cells to assume respective first programming levels. Second data bits are stored in the set of memory cells at a second time that is later than the first time by programming the memory cells to assume respective second programming levels that depend on the first programming levels and on the second data bits. A storage strategy is selected responsively to a difference between the first and second times. The storage strategy is applied to at least one group of the data bits, selected from among the first data bits and the second data bits.

Abstract: A method for data storage includes defining a set of scrambling sequences, each sequence including bits in respective bit positions having bit values, such that a distribution of the bit values in any give bit position satisfies a predefined statistical criterion. Each data word is scrambled using a respective scrambling sequence selected from the set. The scrambled data words are stored in the memory device.

Abstract: A method for data storage in a memory that includes multiple analog memory cells fabricated using respective physical media, includes identifying a group of the memory cells whose physical media have deteriorated over time below a given storage quality level. A rejuvenation process, which causes the physical media of the memory cells in the group to meet the given storage quality level, is applied to the identified group. Data is stored in the rejuvenated group of the memory cells.

Abstract: A method for data storage includes storing data, which is encoded with an Error Correction Code (ECC), in a group of analog memory cells by writing respective first storage values to the memory cells in the group. After storing the data, respective second storage values are read from the memory cells in the group, and the read second storage values are processed so as to decode the ECC. Responsively to a failure in decoding the ECC, one or more of the second storage values that potentially caused the failure are identified as suspect storage values. Respective third storage values are re-read from a subset of the memory cells that includes the memory cells holding the suspect storage values. The ECC is re-decoded using the third storage values so as to reconstruct the stored data.

Abstract: A method for data storage includes defining, in a memory that includes multiple analog memory cells, an erased state, a set of non-erased programming states and a partial subset of the non-erased programming states. Data is initially stored in a first group of the analog memory cells by programming each of at least some of the memory cells in the first group from the erased state to a respective non-erased programming state selected from the set of non-erased programming states. After initially storing the data, a second group of the analog memory cells, which potentially cause interference to the first group, is programmed. After programming the second group, the first group is selectively re-programmed with the data by repeating programming of only the memory cells in the first group whose respective programming states belong to the partial subset.

Abstract: A method for data storage includes defining a first programming scheme that programs a group of analog memory cells while reducing interference caused by at least one memory cell that neighbors the group, and a second programming scheme that programs the group of the analog memory cells and does not reduce all of the interference reduced by the first programming scheme. One of the first and second programming schemes is selected based on a criterion defined with respect to the analog memory cells. Data is stored in the group of the analog memory cells using the selected programming scheme.

Abstract: A method for data storage includes defining a first programming scheme that programs a group of analog memory cells while reducing interference caused by at least one memory cell that neighbors the group, and a second programming scheme that programs the group of the analog memory cells and does not reduce all of the interference reduced by the first programming scheme. One of the first and second programming schemes is selected based on a criterion defined with respect to the analog memory cells. Data is stored in the group of the analog memory cells using the selected programming scheme.

Abstract: A method for data storage includes storing data, which is encoded with an Error Correction Code (ECC), in a group of analog memory cells by writing respective first storage values to the memory cells in the group. After storing the data, respective second storage values are read from the memory cells in the group, and the read second storage values are processed so as to decode the ECC. Responsively to a failure in decoding the ECC, one or more of the second storage values that potentially caused the failure are identified as suspect storage values. Respective third storage values are re-read from a subset of the memory cells that includes the memory cells holding the suspect storage values. The ECC is re-decoded using the third storage values so as to reconstruct the stored data.