For a nonvolatile memory permitting electrical writing and erasing of information to be stored, such as a flash memory, the load on the system developer is to be reduced, and it is to be made possible to avoid, even if such important data for the system as management and address translation information are damaged, an abnormal state in which the system becomes unable to operate. A P frame image is to be repositioned from an original position to an alternate position. The LED is mounted on an end of the radiation fin. The second element is removably attached to any position of the transparent portion of the casing. In yet another aspect, a poise element with an edge formed according to y=1 is formed, where m is any number.