Data management in flash memory using probability of charge disturbances

摘要

A Flash memory system and a method for data management using the system's sensitivity to charge-disturbing operations and the history of charge-disturbing operations executed by the system are described. In an embodiment of the invention, the sensitivity to charge-disturbing operations is embodied in a disturb-strength matrix in which selected operations have an associated numerical value that is an estimate of the relative strength of that operation to cause disturbances in charge that result in data errors. The disturb-strength matrix should also include the direction of the error which indicates either a gain or loss of charge. The disturb-strength matrix can be determined by the device conducting a self-test in which changes in the measured dispersion value are provoked by executing a selected operation until a detectable change occurs. In alternative embodiments the disturb-strength matrix is determined by testing selected units from a homogeneous population.