Experience with testing and rigorous program analysis for qualification of RTOS

Real Time Operating System (RTOS) is a critical component of embedded systems. International standards such as IEC60880 used for development of Instrumentation and Control (I&C) system in nuclear power plants require rigorous qualification of all software components. In this paper, we describe our experience in qualification of ESOS; an in-house configured RTOS from a commercial RTOS available with source code. The qualification activities include static & dynamic analysis, timing analysis and rigorous program analysis. We discuss how rigorous program analysis was used to uncover a subtle bug in the implementation.