ROS: Personal Robotics and Open Source - Robotic Operating System

What is ROS?

ROS is an open-source, meta-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. It also provides tools and libraries for obtaining, building, writing, and running code across multiple computers.

http://www.ros.org/wiki/ROS/Introduction

Personal Robotics and Open Source: An Introduction to ROS

ROS is an open-source, meta-operating system for personal robotics. It provides services like an operating system, including hardware abstraction, low-level device control, implementation of commonly-used functionality, message-passing between processes, and package management. It also provides tools and libraries for obtaining, building, writing, and running code across multiple computers.
ROS provides a shared software platform to support robotics research and application development. For researchers, the common platform means that scientists can reproduce each others’ robotics experiments and directly build on previous results, leading to better scientific practice. For developers, it means that innovative robotics applications can be shared and used across many different robots. For hobbyists and hackers, it means that sophisticated capabilities, from autonomous navigation to object recognition, are within reach. ROS can be seen (depending on your perspective) as the Linux or the Android of robotics.
Together with Stanford University, Willow Garage launched ROS in 2007. Since that time, a significant and burgeoning ROS community has developed. Currently, there are approximately 2,000 ROS packages, nearly 80 publicly accessible repositories of ROS code, and over 50 robots using ROS, including mobile manipulators, quadrotors, cars, boats, space rovers, hobby platforms, and more.