An apparatus having switchable servo gains and offsets for an optical disk drive adjusts its gains and offsets through the coupling of a servo signal and a switch with several changeable paths. The data processing system has a plurality of data processing nodes distributed across a network. In rearranging data stored in one logical device group to another logical device group, a management server connected to the switch sends an update request to the switch and makes it update the correspondence in the table. The rotating shaft is mounted with a plurality of cutting blade blocks.