Bad page marking strategy for fast readout in memory

Abstract

A technique for identifying bad pages of storage elements in a memory device. A flag byte is provided for each page group of one or more pages which indicates whether the page group is healthy. Flag bytes of selected page groups also indicate whether larger sets of page groups are healthy, according to bit positions in the flag bytes. A bad page identification process includes reading the flag bytes with a selected granularity so that not all flag bytes are read. Optionally, a drill down process reads flag bytes for smaller sets of page groups when a larger set of page groups is identified as having at least one bad page. This allows the bad page groups to be identified and marked with greater specificity. Redundant copies of flag bytes may be stored in different locations of the memory device. A majority vote process assigns a value to each bit.