1. A memory system, comprising: a first sub-memory comprising at least one nonvolatile memory; a second sub-memory comprising at least one volatile memory; wherein in response to a memory reference failure that has occurred in a cache memory, a reference failed data is always first loaded and stored to the second sub-memory from a storage regardless of the type of the memory reference failure, all the data stored to the second sub-memory from the storage is transferred and stored to the first sub-memory, the first-sub-memory only stores data transferred from the second sub-memory, and all the data of the first sub-memory transferred from the second sub-memory is sent to the cache memory.