A method, system, apparatus, and computer readable medium storing
instructions for recording data tracks and a method and system for
reading data tracks. For recording data tracks, virtual boundary of a
first data track recorded on the storage medium is determined. The
recording element is positioned based on the determined virtual boundary
of the first track and a second data track is recorded by the positioned
recording element. For reading data tracks, a first virtual boundary of a
first data track and a second virtual boundary of the first data track
are determined and a reading element is positioned at a center of the
first data track based on the determined virtual boundaries. In the
system of reading recorded data tracks, a number of forward reading
elements and backward reading elements are provided. The forward reading
elements have different pitches.