Patent ID: 7996736
Filing Date: 2011-08-09
Classification: G11C

Abstract:
1. A method for operating a memory device which includes storage elements arranged in units, comprising: identifying fault statuses of units of storage elements of the memory device, the units of storage elements have associated flag bytes stored in the memory device, where: (a) the fault statuses of the units are provided according to a hierarchy having at least three levels, from fault statuses for smallest units at a lowest level of the hierarchy to fault statuses for largest units at a highest level of the hierarchy, and (b) different bit positions of the flag bytes are associated with different levels of the hierarchy to indicate whether units of storage elements of the different levels include at least one faulty storage element; the identifying comprises reading initially selected ones of the flag bytes according to an initially selected level of the hierarchy, evaluating bits of the initially selected flag bytes whose bit position corresponds to the initially selected level of the hierarchy, and, based on the evaluating, determining whether it is necessary to read additional ones of the flag bytes to identify fault statuses of the units of storage elements; and based on the identifying, preparing a map which indicates units of storage elements of the memory device which are to be treated as being faulty.