This manual explains the software of the Robot Force and Motion Server (RFMS), a high performance robot control system designed and implemented in the GRASP laboratory. In this system, the robot manipulator is considered a force/motion server to the robot and a user application is treated as a request for the service of the manipulator. The user application is created on one of the Unix/VAX machines in 'C' programming language as a set of function calls. The application is carried out in a multi-processor controller, which consists of Intel single board computers and provides computing power necessary for computationally intensive tasks. The VAX machine and the Intel controller communicate through Ethernet, a local area network, which also allows interaction between the user and sensors. Design principles of the system can be found in Section 2.