A nonvolatile memory system includes nonvolatile memory organized into blocks, one or more of which are designated as spare blocks and one or more of which may be defective at the time of manufacturing of the nonvolatile memory. A controller device is coupled to the nonvolatile memory for measuring the...http://www.google.com/patents/US7464306?utm_source=gb-gplus-sharePatent US7464306 - Status of overall health of nonvolatile memory
