A Distributed Real-Time Operating System with Distributed Shared Memory for Embedded Control Systems

The paper presents a distributed real-time operating system (DRTOS) that provides a distributed shared memory (DSM) service for distributed control systems. Model-based design has become popular in embedded control software design and the source code of software modules can be generated from a controller model. The generated software modules exchange their input and output values through shared variables. We develop a DRTOS with a real-time DSM service to provide a location-transparent environment, in which distributed software modules can exchange input and output values through the DSM. The DRTOS is an extension to OSEK OS. We use a real-time network called FlexRay, which is based on a TDMA (Time Division Multiple Access) protocol. The consistency of the DSM is maintained according to the order of data transfer through FlexRay, not using inter-node synchronization. The worst case response time of the DSM is predictable if the FlexRay communication is well configured.