Software architecture supporting integrated real-time systems

To achieve reliability, reusability, and cost reduction, a significant trend in building large complex real-time systems is to integrate separate application modules of different criticalities in a common hardware platform. An essential requirement of integrated real-time systems is to guarantee spatial and temporal partitioning among applications in order to ensure an exclusive access of physical and temporal resources to the applications. In this paper we propose software architecture, implemented as SPIRIT-μKernel, for strongly partitioned integrated real-time systems. The SPIRIT-μKernel has been designed and implemented based on a two-level hierarchical scheduling methodology such that the real-time constraints of each application can be guaranteed. To demonstrate the feasibility of the SPIRIT-μKernel, we have ported two real-time operating systems (RTOS), WindRiver's VxWorks and Cygnus's eCos, on the top of the microkernel. Thus, different RTOS can be applied in various partitions to provide required features for each application. Based on the measured performance results, the SPIRIT-μKernel architecture is practical and appealing due to its low overheads of kernel services and the support for dependable integration of real-time applications via scheduling algorithm.