ABSTRACT

This chapter acquaints the reader with the real-time operating system (RTOS) and the associated avionics application software standard widely used in digital avionics systems. It addresses the following questions: Why use an avionics RTOS? What makes an avionics RTOS different from general computer RTOS? What are the basic concepts? and how do they work?. ARINC Specification 653 was written to define software modules at an abstract level and, in particular, define the interface boundary between the application software modules and the underlying computer operating system, also called the RTOS. The RTOS creates a uniform environment that allows software modules or applications to execute and provides a standard set of system services to schedule software execution, map memory areas, and, in some cases, partition memory accesses, perform input/output (I/O) operations, and handle errors or faults. The ARINC 653 software interface specification was developed for Integrated Modular Avionics systems and for federated equipment that may contain more than one partitioned function.