Abstract. CCSP is a highly portable run-time system that conforms to the ideas of CSP and supports both the C and occam programming languages. Its aim is to further the use of the CSP mind-set in both industrial and academic applications. The run-time system implements a useful and efficient subset of the basic CSP constructs. It allows occam-style designs to be programmed in C, thereby allowing full use of the optimisation phases of standard C compilers. It supports the KRoC occam system for Linux/PC platforms. In addition, a number of features have emerged from industrial collaboration as essential for soft real-time systems in the real world. These include: prioritised scheduling with 32 priority levels, integration of communications hardware to provide support for distributed processing, and access to a highly accurate real-time clock. This paper discusses the high level structure and functionality of the features provided.