monitor, or visual display, is simply the portal that allows one to  interact with the technology. The display (be it visual, auditory, tactile,  etc.) is an artifact designed to support the perception of relevant system  variables and to facilitate further processing of that information. Before a  display is designed, the task that the display is intended to support must be  defined (e.g. navigating, controlling, decision making, learning, entertaining,  etc.). A user or operator must be able to process whatever information that a  system generates and displays; therefore, the information must be displayed  according to principles in a manner that will support perception, situation  awareness, and understanding.