Patent ID: 7953931

Claim:
A method of managing data transfer operations in a high endurance non-volatile memory device (NVMD) adapted to a host computer system, the NVMD comprises a volatile memory as a data cache subsystem and at least one non-volatile memory module as a data storage of the host, the method comprises: receiving a data transfer request including a logical sector address (LSA) of data to be transferred from the host computer system; determining whether a ‘cache-hit’ or a ‘cache-miss’ status in the data cache subsystem according to an index and a tag derived from the received LSA, the ‘cache-hit’ status represents a ‘cache-hit’ cache line contains relevant data; determining whether the data transfer request is a read or a write operation; when the read operation and the ‘cache-hit’ are determined, retrieving requested data from the ‘cache-hit’ cache line and sending to the host; and updating a cache usage status; when the read operation and the ‘cache-miss’ are determined, loading the request data from the at least one non-volatile memory module based on the received LSA to a least-recently used (LRU) cache line in the data cache subsystem; sending the requested data to the host; and updating a cache usage status; when the write operation and the ‘cache-hit’ are determined, writing incoming data to ‘cache-hit’ cache line; updating the cache usage status; and storing the incoming data into the at least one non-volatile memory module according to the received LSA; and when the write operation and the ‘cache-miss’ are determined, writing the incoming data to the LRU cache line; updating the cache usage status; and storing the incoming data into the at least one non-volatile memory module according to the received LSA; wherein the at least one non-volatile memory module includes Single-Level Cell flash memory (SLC) and Multi-Level Cell flash memory (MLC) and said storing the incoming data into the at least one non-volatile memory module according to the received LSA further comprises: if SLC data programming rules allow, storing the incoming data to a block corresponding to the physical address in the SLC, otherwise storing the incoming data to a new available SLC block; when the SLC has been used up to its capacity, a lowest hit block in the SLC is copied to a new MLC block for reuse, the new MLC block is allocated according to a selection process using a probability density function along with a pseudo random number generator.