US Patent 9411717 Metadata journaling with error correction redundancy

Method and apparatus for managing a memory, such as but not limited to a flash memory. In accordance with some embodiments, user data and associated metadata are stored in a memory. The metadata are arranged as a first sequence of snapshots of the metadata at different points in time during the operation of the memory, and a second sequence of intervening journals which reflect updates to the metadata from one snapshot to the next. Requested portions of the metadata are recovered from the memory using a selected snapshot in the first sequence and first and second journals in the second sequence.