Adapting Linux for mobile platforms: An empirical study of Android

To deliver a high quality software system in a short release cycle time, many software organizations chose to reuse existing mature software systems. Google has adapted one of the most reused computer operating systems (i.e., Linux) into an operating system for mobile devices (i.e., Android). The Android mobile operating system has become one of the most popular adaptations of the Linux kernel with approximately 60 millions new mobile devices running Android each year. Despite many studies on Linux, none have investigated the challenges and benefits of reusing and adapting the Linux kernel to mobile platforms. In this paper, we conduct an empirical study to understand how Android adapts the Linux kernel. Using software repositories from Linux and Android, we assess the effort needed to reuse and adapt the Linux kernel into Android. Results show that (1) only 0.7% of files from the Linux kernel are modified when reused for a mobile platform; (2) only 5% of Android files are affected by the merging of changes on files from the Linux repository to the Android repository; and (3) 95% of bugs experienced by users of the Android kernel are fixed in the Linux kernel repository. These results can help development teams to better plan software adaptations.