A system, method, computer program and apparatus for providing regulating
signals for regulating the position of an objective lens relative to a
track on a disk. The regulating signals are obtained in response to an
access request specifying an access target region on the disk. The tracks
of a disc are divided into a plurality of zones, each zone having
associated signal regulation information. In response to an access
request, the signal regulation information for the zone containing the
access target region is used to regulate the position of the objective
lens.