1. A method of operating a memory system including a flash memory and a memory controller having a cache memory and a nonvolatile random access memory (NVRAM), the method comprising: receiving a write request specifying a write operation to the flash memory; loading a page mapping table for a block of flash memory to the cache memory, wherein the block is corresponding to the write request; generating update information for the page mapping table loaded in the cache memory as a result of executing the write operation, and storing the update information in the NVRAM; and storing an updated version of the page mapping in the flash memory after execution of the write operation is complete.