Abstract: In a card storage device containing a non-volatile memory and a buffer memory, the buffer memory includes a plurality of banks. Data is transferred sequentially from a host CPU to the banks of the buffer memory, data is transferred to the non-volatile memory from a bank that becomes full, a write operation is started when one unit of data to be written into the non-volatile memory at a time has been transferred and, without waiting for the data to be written, the next write data is transferred from the host CPU to a bank from which write data has been transferred.

Abstract: The present invention provides a memory card in which stored information is not lost undesirably even when an operation power source is shut down during an erasing/writing process. A nonvolatile memory has an erase table in which a free-space information flag is associated with each physical address of a memory area and an address translation table in which a physical address of a memory area is associated with each logical address. The free-space information flag indicates whether a corresponding memory area is permitted to be erased or not. A control circuit determines a memory area to which rewrite data is to be written by referring to the free-space information flag of the erase table, reflects the physical address and the logical address of the memory area to which the data is written into the address translation table, and updates the free-space information flag of the erase table.

Abstract: In a card storage device containing a non-volatile memory and a buffer memory, the buffer memory includes a plurality of banks. Data is transferred sequentially from a host CPU to the banks of the buffer memory, data is transferred to the non-volatile memory from a bank that becomes full, a write operation is started when one unit of data to be written into the non-volatile memory at a time has been transferred and, without waiting for the data to be written, the next write data is transferred from the host CPU to a bank from which write data has been transferred.