A method is provided for laser optically marking integrated circuit packages in a non-destructive manner. An erasing apparatus includes: the recording medium identifying device; a heating device configured to heat the recording medium to temperature equal to or higher than erasing temperature; a switching mechanism configured to switch a recording medium conveying path; and a disposal box in which unusable recording media are stored. Magnets are mounted to the stator andor the mover. The radial correction factors are then added to the measured position information during read andor write operations of the data storage system. The method includes the step of administering to the infant a nutritional composition including from about 3 weight % phospholipids to about 20 weight % phospholipids, based on total fat of the nutritional composition.