Robot Operating System
"ROS is an operating system for your robot. It provides the services you would expect from an operating system, including hardware abstraction, low-level device control, implementation of commonly-used functionality, message-passing between processes, and package management. ROS is similar in some respects to 'robot frameworks,' such as Player, CARMEN, Orca, MOOS, and Microsoft Robotics Studio.
The primary goal of ROS is to enable code reuse in robotics research and development. We aim to make it easy to reuse code at every level, and make it easy for anybody to publish code for reuse by others." (http://pr.willowgarage.com/wiki/ROS)