A method and apparatus for a checker instruction in a redundant multithreading environment is described. In another aspect of the present description, the test wafer may be positioned using a positioner having a first plurality of test wafer engagement members positioned around the pedestal central wafer support surface. The invention enables a driver to correctly know the condition of the battery in substantially real time while consuming a minimum amount of current. The motor system is configured to drive at least one of the wiper fluid from the first reservoir and the de-icing fluid from the second reservoir. The approach permits the rapid visualization of proteins that are at the limits of detection using traditional methods. The two images can be seen simultaneously, providing a composite image.