Patent ID: 6647471
Filing Date: 2003-11-11
Classification: G06F,G11C,Y10S

Abstract:
A method or overwriting data in a memory device comprising a first and second set of memory cells, the method comprising:(a) storing data in a first set of memory cells in a memory device; (b) storing an error code in a second set of memory cells in the memory device, the error code representing the data stored in the first set of memory cells; (c) writing a destructive pattern into at least some of the first set of memory cells, wherein the error code no longer represents the data stored in the first set of memory cells after the destructive pattern is written and wherein the destructive pattern introduces an error in the data that is correctable by the error code stored in the second set of memory cells; (d) storing a flag in a third set of memory cells in the memory device indicating that the data is deleted data; (e) with a file system, determining whether the flag was stored in the third set of memory cells; and (f) if the file system determines that the flag was stored in the third set of memory cells, allowing the data to remain uncorrected even though the error is correctable.