An optical switch uses a fixed mirror cover to reflect optical signals to and from fiber collimators and movable mirrors that are formed on a common substrate. The method may include using a test host that has both control and data inputoutput capabilities. The arrival signals identify when a processor chip executes a synchronization operation for synchronizing the tasks for the MPI job. The second energy is one which acts synergistically with the first energy to impart the desired physical change. It comprises abutment means bearing on the first shoulders of the outer body, and a helical spring provided between the front portion of the cylindrical guide and the abutment means of the ferrule holder. The exerciser may include a resilient resistance system coupled to the movable body carriage and a set of pull lines with user grips trained over pulleys carried by the exerciser frame.