In this chapter we have learned to install two different versions of ROS (Electric and Fuerte) in Ubuntu. With these steps, you have all the necessary software installed on your system to start working with ROS and the examples of this book. You can install ROS using the source code as well. This option is for advanced users, and we recommend that you use this repository only for installation; it is more common and normally it should not give errors or problems.
It is a good idea to play with ROS and the installation on a virtual machine. This way, if you have problems with the installation or with something, you can reinstall a new copy of your operating system and start again.
Normally, with virtual machines, you will not have access to real hardware, such as sensors and actuators. Anyway, you can use it for testing algorithms, for example.
In the next chapter, you will learn the architecture of ROS, some important concepts, and some tools to interact directly with ROS.