Patent ID: 7725743

Claim:
A mobile device with an index creation function, comprising: a file storage portion that stores files; a file reading portion capable of reading the contents of the files stored in the file storage portion; an index creating portion that controls the file reading portion so as to read the contents of the files stored in the file storage portion and that creates index data that can be used for searching of the contents of the files read by the file reading portion; an electric storage portion capable of being charged/discharged; an electric energy input/output portion capable of acquiring electric energy input from the electric storage portion and an external power source, and capable of outputting electric energy to the electric storage portion, the file reading portion, and the index creating portion; and an index creation determining portion that permits the index creating portion to create the index data when an index creation condition that the electric energy input/output portion can acquire electric energy input from the external power source is satisfied, and that does not permit the index creating portion to create the index data when the index creation condition is not satisfied.