Position verifying apparatus and method, position measuring apparatus and method, and computer program for position verification or position measurement
A position verifying apparatus is provided with: a first recording device for recording the information into a first area of the first recording layer; a second recording device for recording a part of the information by laser light which has penetrated the first area and for recording another part of the information by laser light which does not penetrate the first area, into a second area of the second recording layer including at least a partial area which faces the first area; a reproducing device for reproducing the information; and a judging device for judging whether or not the relative shift is within tolerance, on the basis of a transit position at which reproduction quality transits from the reproduction quality indicated by the part of the information reproduced to the reproduction quality indicated by the another part of the information reproduced.
