Abstract: A radial gap type medium driving motor for rotating a recording medium has first coil units having first windings of a first number of layers and second coil units having second windings of a second number of layers that is larger than the first number of layers. The first and second coil units are formed by winding wire on tooth-like poles of tooth-like pole blocks of a stator. A frame provided with a bearing portion for rotatably supporting the medium driving motor has a first accommodating portion for accommodating the first coil units and second accommodating portions for accommodating the second coil units.

Abstract: A magnetic head assembly comprises a magnetic head, a magnetic head support structure having a first mount, a second mount and a housing space, and an optical unit fixed to the second mount, capable of projecting a plurality of light beams through a light passage on a recording medium and of receiving a plurality of reflected light beam. The optical unit comprises a light emitting device which emits a light beam, a holographic unit capable of producing a plurality of light beams from the light beam and of focusing the plurality of light beams on a position sensing track formed on the recording medium, and a photodetection device for receiving the plurality of reflected light beams. The holographic unit is partly received in the housing space.