Method of archiving data

A method and system for archiving data. The data are classified according to their desired lifetime and then archived in a memory using a storage method whose reliability is in accordance with the desired lifetime. For example, when storing data in the cells of an EPROM, short-term data could be archived using larger programming voltage pulse increments than for long-term data, using a lower target threshold voltage than for long-term data, using wider programming voltage pulses than for long-term data, using higher starting programming voltages than for long-term data, using fewer programming voltage pulses than for long term data, using lower maximum programming voltages than for long term data, or using more levels per cell than for long-term data.