Patent ID: 7346730

Claim:
A mobile electronic device comprising: a first data memory configured to store data; a second data memory configured to store data equivalent to the data stored in the first data memory; a determining section configured to determine which one of the data stored in the first data memory and data stored in the second data memory is newest data; a writing section configured to perform a writing process with respect to one of the first and second data memories which stores data determined not to be the newest data by the determining section; a management memory configured to store determination information indicating which one of the data stored in the first data memory and the data stored in the second data memory is the newest data such that the determining section determines one of the data memories which stores the newest data based on the determination information stored in the management memory, wherein the management memory includes first and second management memories, and the determining section determines which one of information stored in the first management memory and information stored in the second management memory is the newest determination information and determines one of the data memories which stores the newest data based on the newest determination information.