File access rates of processes are regulated according to file type. The method further includes irradiating the pixels in multiple scans over the surface with radiation having different, respective types of polarization, and detecting returning radiation from the pixels in response to each of the scans. A reagent layer is disposed in the sample chamber. In addition a micro-mechanical optical element is packaged with the laser array, such that the position of the optical element controls which laser stripe is coupled to the output fiber. A preferred embodiment’s physical subsystems combine to form a scalable holistic system that can be able to conduct tests for thousands of customers any place in the world.