Patent ID: 7251717

Claim:
A semiconductor memory device comprising: memory means for allocating a plurality of physical address memories and a plurality of address identification data areas with respect to one logical address; write destination selecting means for selecting an empty physical address memory among said plurality of physical address memories based upon address identification data of said address identification data areas, said empty physical address memory corresponding to said one logical address; writing means for writing data into said selected empty physical address memory, wherein said writing means writes new data while retaining the previous written data stored in a different physical address memory which corresponds to said one logical address; read destination selecting means for selecting a physical address memory into which the data has been written at last among said plurality of physical address memories based upon the address identification data of said address identification data areas; reading means for reading the data from said selected physical address memory into which the data has been written at last, wherein said read destination selecting means designates the address identification data areas provided in correspondence with the physical addresses with said one logical address in the address order so as to read address identification data, and selects an empty physical address memory based upon a read result generated by said reading means, and also, selects physical address memory having an address preceding to said selected empty physical address memory by 1 as the physical address memory into which the data has been written at last.