Abstract: A method and apparatus of wear leveling control for storage class memory are disclosed. According to the present invention, where current data to be written to a nonvolatile memory corresponds to an address cache hit is determined. If the current data to be written corresponds to an address cache hit, the current data are written to a designated location in the nonvolatile memory different from a destined location in the nonvolatile memory. If the current data to be written corresponds to an address cache miss, the current data are written to the destined location in the nonvolatile memory. In another embodiment, the wear leveling control technique also includes address rotation process to achieve long-term wear leveling as well.

Abstract: A method and apparatus for read wearing control for storage class memory (SCM) are disclosed. The read data control apparatus, located between a host and the SCM subsystem, comprises a read data cache, an address cache and an SCM controller. The address cache stores pointers pointing to data stored in logging area(s) located in the SCM. For a read request, the read wearing control determines whether the read request is a read data cache hit, an address cache hit or neither (i.e., read data cache miss and address cache miss). For the read data cache hit, the requested data is returned from the read data cache. For the address cache hit, the requested data is returned from the logging area(s) and the read data becomes a candidate to be placed in the read data cache. For read data cache and address cache misses, the requested data is returned from SCM.

Abstract: A method and apparatus of wear leveling control for storage class memory are disclosed. According to the present invention, whether current data to be written to a nonvolatile memory corresponds to a write cache hit is determined. If the current data to be written corresponds to the write cache hit, the current data are written to a write cache as well as to a designated location in the nonvolatile memory different from a destined location in the nonvolatile memory. If the current data to be written corresponds to a write cache miss, the current data are written to the destined location in the nonvolatile memory. If the current data to be written corresponds to the write cache miss and the write cache is not full, the current data is also written to the write cache. In another embodiment, the wear leveling control technique also includes address rotation process to achieve long-term wear leveling as well.