Patent 7818493 was granted and assigned to SanDisk on October, 2010 by the United States Patent and Trademark Office.
In a nonvolatile memory array, selected blocks are maintained as open blocks that are available to store additional data without being erased first. Nonsequential open blocks are selected from two lists, one list based on recency of the last write operation, and the other list based on frequency of writes to the block. Sequential open blocks are divided into blocks expected to remain sequential and blocks that are not expected to remain sequential.