An integrated circuit for controlling a data storage device. In a common rail type fuel injection control apparatus, a pressure control valve 12 is provided in a fuel return path from a common rail 1, and a rail pressure detected by a pressure sensor 11 can be controlled to match a target rail pressure through drive control of the pressure control valve 12 by an electronic control unit 4. A first of multiple side by side pairs of seal assemblies and contact assemblies in the bore is proximate the block member, a last one is nearest the bore entrance.