A Real-Time Operating System with CAN-Based Inter-Node Shared Resource Management and Distributed Shared Memory

The paper presents a real-time operating system (RTOS) that supports location-transparent shared resource management and distributed shared memory for distributed embedded control systems with CAN (Control Area Network) buses. In a distributed embedded control system, location-transparent mechanisms are required because application tasks are distributed to a number of nodes. We have developed a RTOS that supports location-transparent inter-node shared resource management and distributed shared memory. The inter-node resource access protocol is based on the Multiprocessor Priority Ceiling Protocol and inter-node locking is efficiently implemented using the arbitration mechanism of CAN. The distributed shared memory with mutual exclusion is also efficiently implemented. The RTOS is an extension to OSEK OS and supports not only inter-node resource management but also inter-core resource management for multi-core processors and inter-core and inter-node system calls for task management and event control. We have evaluated the performance of the RTOS and have confirmed that the performance is acceptable for practical embedded control systems.