Timing Predictability in Real-Time Systems

A real-time system must be not only functionally correct, but also temporally correct. With the trend of real-time applications being used in safety critical situations, the ability to predict the timing properties of such systems is becoming more important than ever. This paper examines some of the general issues involved in making timing predictions with the focus on shared resources and interprocessor communication. Four systems used to implement real-time applications are analyzed for predictability: a real-time kernel from UBC, YARTOS, Chimera II, and MARS. The UBC real-time kernel and YARTOS are intended for uniprocessor systems and have been used in multimedia applications. Chimera II, a robotics environment, and MARS, a fault-tolerant architecture, are both multiple processor environments. Timing Predictability in Real-Time Systems 1