This paper presents an investigation into the inter-processor and inter-process communication for real-time computing in multiprocessing systems. A finite difference simulation algorithm of a flexible beam is considered to demonstrate critical inter-processor and inter-process communication issues in real-time computing. Accordingly, issues such as, synchronization, sharing process resources, granularity, scheduling and mapping are explored within the framework of real-time parallel processing and parallel multithreading. The algorithm is also analysed in detail to explore the inherent data dependencies that impact on the inter-processor and inter-process communication. Finally, a comparison of the results of the implementations is made on the basis of real-time performance to lead to merits of systems design incorporating fast processing techniques for real-time applications.