Apparatus and Method of Damage Recovery for Storage Class Memory

An apparatus for damage recovery of storage class memory based on nonvolatile memory, the apparatus comprising:

• a cache memory;
• a storage class memory (SCM) controller coupled to the cache memory and a nonvolatile memory, wherein input data is written to a selected write cache location as well as a selected nonvolatile memory location, the selected write cache location includes a timestamp, and contents in the selected nonvolatile memory location are flushed to a destined location in the nonvolatile memory if the timestamp indicates that the in the selected nonvolatile memory location are aged;
• and
• one or more processors;
• wherein the cache memory, the SCM controller and said one or more processors are configured to perform at least the following:
• divide the nonvolatile memory into memory groups;
• and
• map N input group addresses corresponding to logic addresses of the memory groups to M output group addresses corresponding to physical group addresses of the memory groups using fixed mapping within a period T, where M and N are positive integers and M is greater than N, wherein N memory groups are used as data groups, and one or more memory groups are used as redundant groups, M is equal to a sum of N and number of the redundant groups, and wherein N input group addresses are mapped to M output group addresses causes N data groups among M memory groups to store the input data in a rotated fashion;
• and
• if a damaged address location in one of the data groups is found:
• create a repair entry in the cache memory for the damaged address location with a last known correct data content;
• and
• update the repair entry in the cache memory by updating the timestamp of the repair entry to prevent the contents in the repair entry from being flushed to the damaged address location.