COTS CPU selection guidelines for safety-critical applications

Despite the frequent use of commercial-off-the-shelf (COTS.) microprocessors throughout the avionics community today, many companies still struggle with choosing the right ones for their forthcoming projects. This paper discusses selection issues concerning the possibilities to use COTS microprocessors (CPUs)(1) in safety critical applications. Issues addressed in the paper include technical, e.g. new on-chip features such as monitors, performance trends and derating concerns, and strategic, e.g. the continuously decreasing short commercial life and lack of predictable roadmaps. We also look at other selection concerns such as certification and environmental directives, e.g. the new Reduction of Hazardous Substances (RoHS).