STORAGE DEVICE

摘要

A storage device is provided to realize improvement in writing tolerance of a nonvolatile memory and improvement in data transfer rate for writing-in and reading-out operations. The memory device is comprised of a nonvolatile memory (101), a volatile memory (106) for storing file management information of the nonvolatile memory (101), a controller (103) for controlling the nonvolatile memory (101) and the volatile memory (106), and a power maintaining unit (105) for supplying power to the volatile memory (106) or the controller (103) when a power source turns off. The controller (103) reads out the file management information stored in the nonvolatile memory (101) and writes it in the volatile memory (106) when the power source starts up. At reading-out and writing-in operations, the operations are carried out in accordance with the file management information stored in the volatile memory (106). When the power source turns off, the file management information stored in the volatile memory (106) is read out and is written in the nonvolatile memory (101).