An apparatus, system, and method are disclosed to increase data integrity in a redundant storage system. Means for attaching or holding a writing implement is provided on the apparatus. A processor 16 detects a defect, using pixels located in the vertical and horizontal directions relative to, in lines of the same color as, and separated by one line from, the focused line. The initiation energy interacts with the energy modulation agent to directly or indirectly produce the change in the medium. The videocamera is connected to an electronic image processing device. The invention also provides a single unit dose of the composition.