In Chapter 1, Understanding the Architecture, we learned how Android has been designed and built around the Linux kernel. One of the reasons to choose the Linux kernel was its unquestioned flexibility and the infinite possibilities to adjust it to any specific scenario and requirement. These are the features that have made Linux the most popular kernel in the embedded industry.
Linux kernel comes with a GPL license. This particular license allowed Google to contribute to the project since the early stages of Android. Google provided bug fixing and new features, helping Linux to overcome a few obstacles and limitations of the 2.6 version. In the beginning, Linux 2.6.32 was the most popular version for the most part of the Android device market. Nowadays, we see more and more devices shipping with the new 3.x versions.
The following screenshot shows the current build for the official Google Motorola Nexus 6, with kernel 3.10.40:
The Android version we created in...
