Abstract: A method for data storage includes accepting data for storage in a memory (28) that includes multiple analog memory cells (32). The data is converted to input values. The input values are filtered using a non-linear filtering operation to produce respective shaped values, and the shaped values are converted to output values using a linear spreading transformation with coefficients chosen so that each of the shaped values contributes to at least two of the output values. The non-linear filtering operation is selected so as to reduce a size of an output range in which the output values lie. The output values are stored in the respective analog memory cells.

Abstract: A method for operating a memory includes encoding input data with an Error Correction Code (ECC) to produce input encoded data including first and second sections, such that the ECC is decodable based on the first section at a first redundancy, and based on both the first and the second sections at a second redundancy that is higher than the first redundancy. Output encoded data is read and a condition is evaluated. The input data is reconstructed using a decoding level selected, responsively to the condition, from a first level, at which a first part of the output encoded data corresponding to the first section is processed to decode the ECC at the first redundancy, and a second level, at which the first part and a second part of the output encoded data corresponding to the second section are processed jointly to decode the ECC at the second redundancy.

Abstract: A method for operating a memory (28) includes storing data in a group of analog memory cells (32) of the memory as respective first voltage levels. After storing the data, second voltage levels are read from the respective analog memory cells. The second voltage levels are affected by cross-coupling interference causing the second voltage levels to differ from the respective first voltage levels. Cross-coupling coefficients, which quantify the cross-coupling interference among the analog memory cells, are estimated by processing the second voltage levels. The data stored in the group of analog memory cells is reconstructed from the read second voltage levels using the estimated cross-coupling coefficients.

Abstract: A method for data storage includes accepting data for storage in a memory (28) that includes multiple analog memory cells (32). The data is converted to input values. The input values are filtered using a non-linear filtering operation to produce respective shaped values, and the shaped values are converted to output values using a linear spreading transformation with coefficients chosen so that each of the shaped values contributes to at least two of the output values. The non-linear filtering operation is selected so as to reduce a size of an output range in which the output values lie. The output values are stored in the respective analog memory cells.

Abstract: A method for data storage in a memory that includes a plurality of analog memory cells includes storing data in the memory by writing first storage values to the cells. One or more read reference levels are defined for reading the cells, such that at least one of the read reference levels is negative. After storing the data, second storage values are read from the cells using the read reference levels, so as to reconstruct the stored data. In another disclosed method, data is stored in the memory by mapping the data to first storage values selected from a set of the nominal storage values, and writing the first storage values to the cells. The set of nominal storage values is defined such that at least one of the nominal storage values is negative.