Abstract: A memory system includes a main memory and a memory controller. The main memory includes at least one block which has a plurality of banks. The memory controller includes a plurality of data channels each of which can access at least one bank in the main memory. Each data channel comprises a write first-in-first-out (FIFO) buffer for efficiently supporting cache purge operations and normal write operations, and a reflective write FIFO buffer for efficiently supporting coherent read with simultaneous cache copyback operations. The memory controller selects the proper FIFO or FIFOs depending on the type of data transaction, and selects the proper channel or channels depending on the system bus size, the data transaction size, and the status of the FIFO(s). The memory system can efficiently support data transactions having different data lengths or sizes from a byte to a long burst, and the timing resolution of the memory is enhanced regardless of the bus clock frequency.