Book excerpt: This book constitutes the thoroughly refereed post-proceedings of the 9th International Conference on Real-Time and Embedded Systems and Applications, RTCSA 2003, held in Tainan, Taiwan, in February 2003. The 28 revised full papers and 9 revised short papers presented were carefully reviewed and selected for inclusion in the book. The papers are organized in topical sections on scheduling, networking and communication, embedded systems and environments, pervasive and ubiquitous computing, systems and architectures, resource management, file systems and databases, performance analysis, and tools and development.