STORAGE DEVICE HAVING PLURALITY OF NONVOLATILE MEMORY DEVICES

PROBLEM TO BE SOLVED: To effectively manage an access busy period for at least a plurality of nonvolatile memory devices. SOLUTION: A bit counter 141 counts the number of bits of a second logical value different from a first logical value which is a logical value in a state that a physical block is erased among the bits constituting access data written in nonvolatile memory devices 11-m (m representing any of 0-7) to be accessed or read out from the device 11-m. A timer 142 measures access busy periods at the time of access processing for the devices 11-m. When the value counted by the counter 141 is larger than or equal to a threshold, an MPU 15 updates access busy period information for the nonvolatile memory devices 11-m stored in an access busy period information area 124 based on the access busy period measured by the timer 142. COPYRIGHT: (C)2010,JPO&INPIT