Patent ID: 8874934

Claim:
An operating method for a non-volatile memory device comprising memory cells, the method comprising: randomizing program data to generate randomized program data, wherein the randomized program data is produced by changing bit values among the program data; storing the randomized program data in the memory cells; erasing a portion of the randomized program data to generate erase data; and during a subsequent read operation and in response to flag cell state data stored in the non-volatile memory device, selecting and performing an operation among (1) obtaining stored randomized program data from the memory cells and de-randomizing the stored randomized program data to generate the read data, and (2) obtaining the erase data from the memory cells and generating the read data from the erase data without de-randomizing the erase data, wherein the flag cell state data indicates whether the data to be obtained from the memory cells is erase data or program data.