The demand for close proximity of magnetic head to the medium during operation of magnetic recording devices, high surface smoothness, and high reliability requires that friction and wear of the head-medium interface be minimized. Friction and wear are minimized by suitable selection of interface materials and lubricants, optimization of surface roughness, and operating conditions. This invited paper presents the state of the art of the characterization of surface roughness and modelling of dry and wet solid contacts which are critical to the design of the modern magnetic storage devices.