ABSTRACT
This chapter explains what an Real-Time Operating Systems (RTOS) is, why it is used, how it fits into the typical avionics system, desired RTOS functionality, issues to be addressed when using an RTOS, and some future RTOS-related challenges. Operating systems are primarily resource managers; the main resource they manage is computer hardware in the form of processors, storage, input/output (I/O) devices, communication devices, and data. Safety-critical RTOS are a subset of the general-purpose RTOS and tend to have the following characteristics: deterministic, responsive, controllable, reliable, and fail-safe. The RTOS is the heart of many modern avionics systems. An RTOS can impact software dependability, productivity, and maintainability. The partitioned RTOSs are becoming more common in aviation projects. The goal of most RTOS developers is to isolate the kernel from the hardware in order to allow reuse and portability. The board support package isolates the RTOS from the target computer processing hardware.
