In the previous chapter, we learned how to install ROS. Subsequently, in this chapter, we will look into the ROS architecture and concepts along with its components. Furthermore, we will learn how to create and use the ROS components—nodes, packages messages, services, and much more, with examples.

The ROS architecture and design has been divided into three sections or levels of concepts:

• The ROS filesystem: In this level, a group of concepts is used to explain how ROS is internally formed, the folder structure, and the minimum number of files that it needs to work.
• The ROS computation graph: In this section, we will see all the concepts and mechanisms which are required to set up the ROS computational network and environment, handle all the processes, and communicate with more than a single computer, and so on.

• The ROS community: This level is of great importance; as with most open source software projects, it comprises a set of tools and concepts to share knowledge, algorithms, and code among developers. Moreover, having a strong community not only helps newcomers to understand the intricacies of the technology, as well as solve the most common issues, it is also the main force that drives its growth.