Craig Hartley, Sun Microsystems, Inc.
Indicator lights are often vital for safe and efficient operation and servicing of human/machine systems. Inconsistent and nonintuitive use of color, behavior, placement, and labeling of status indicators increases the probability that users may commit errors in quickly and accurately interpreting the operational status of a component or system. These errors can be enormously costly. Loss of availability of a 911 emergency call center because of a simple error like misidentifying and removing the wrong hard drive can be a matter of life and death.