Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. RTAI-XML is a server component of the Real Time Application Interface (RTAI) project, implementing a service oriented way to design and develop Real Time (RT) control applications. This project was born to fulfill the needs of a university group, mainly focused to have a flexible platform for learning control systems design, allowing the students to test their programs remotely, over the Internet. Leaving the first wishful thinking and going to the real implementation gave rise to the alpha version of RTAI-XML, that showed the potential impact of the basic idea of a net separation of Hard and Soft Real Time tasks in the programmation logic. What was necessary to assure that students could not crash the RT process, is now becoming a new RTAI paradigm. RTAI-XML consists of a server component waiting for incoming calls on a box where a Real Time process, the Target, is running (or ready to).