Patent ID: 7383482

Claim:
An abnormality detecting device comprising: a creating unit that creates a first data pattern including a first value of a cyclic redundancy check data in a cyclic redundancy check data area, the first data pattern being different from a single stored second data pattern created last time; a writing unit that writes the first data pattern as a written data pattern; and a judging unit that reads out a data pattern written in the abnormality detecting device as a read data pattern and judges whether the written data pattern and the read data pattern coincide with each other; wherein the creating unit calculates a second value of a cyclic redundancy check data from the first data pattern, judges whether the first value and the second value coincide with each other by comparing the first value and the second value, and inserts, into the cyclic redundancy check data area, a third value that is different from the first value by creating the third value if the first value and the second value coincide with each other.