Memory card device, and memory card control method for controlling the device

A memory card device includes a host interface unit configured to receive a plurality of commands from a host apparatus, the commands including at least a memory access command with a memory address of a specific bit width, a nonvolatile semiconductor memory which includes a storage area whose memory size is larger than a maximum memory size that is addressable by the memory address, a bank identification number management unit configured to divide the storage area into a plurality of banks and manage a plurality of bank identification numbers corresponding to the banks, a bank designation unit configured to designate one of the banks in accordance with a bank identification number included in a bank designation command transmitted from the host apparatus, and a memory control unit configured to access the designated one of the banks in accordance with the memory access command with the memory address.