Memory controller, memory system with memory controller, and method of controlling flash memory

Abstract

Access to flash memories is controlled so that efficiency of data writing and effective utilization of storage area go together. In the access control, priority order, for physical blocks each storing effective data, is managed so that a position of a physical block in the assignment order becomes higher according as assignment of a logical block to the physical block is performed more recently. When assigning a logical block to a free physical block, a determination is made whether a position of a previous physical block is higher than a predetermined position in the priority order. The previous physical block is a physical block, then, corresponding to the same logical block as the free physical block. When the determination is negative, effective data stored in the previous physical block is transferred to the free physical block.