Abstract: A low-profile radial access mechanism for controlling the radial position of a read/write head relative to a rotating data storage disk (e.g. optical, magneto-optical and magnetic disks). Such mechanism has a carriage (10) which supports a plurality of bearings (11) on its opposing sides. The bearings engage a pair of space parallel rods (21, 31) to guide the carriage along a rectilinear path. Each rod is made of a ferromagnetic material and forms part of the flux-carrying structure of one of a pair of separate electromagnetic linear motors (20, 30). One of the two flux-carrying structures is movable relative to the other to preload the bearings against the guide rods. According to a preferred embodiment, the pair of linear motors share the windings of a single coil (22) carried by the carriage, such windings being physically distributed as to accommodate an exact constraint arrangement provided by the bearings.