Enabling security of a computer system. In some aspects, set of queries are stored. After each optical element is located and inserted into a respective hole, the optical elements are polished to be planar with the surface of the wafer. The system of equations may include variables representative of the parameter vector, the lateral tool displacement vector, and the standoff measurements. The gimbal mount is adapted for angular movement relative to the central longitudinal axis upon angulation of the surgical instrument while substantially maintaining the sealed reception of the surgical instrument.