System services start-up

P. After bootJup, the Linux kernel starts the init process, which is the grandJdaddy of all processes in the system, with a PfD = N. The following steps explain the startJup procedure until the Home screen shows upW N. A set of native services Ewritten in CLCHHF like vold, netd, installd and debuggerd are started. These services have root permission. O. Then the Service Manager and Media Server are started. These run with the system’s permission. init then starts the app_process (frameworks/base/ cmds/app_process/app_main.cpp). This launches the ‘zygote’ process, in a Dalvik sj via frameworks/ base/core/jni/AndroidRuntime.cpp and frameworks/ base/core/java/com/android/internal/os/ZygoteInit. java. This zygote process then becomes the parent of every application. a. then the zygote starts, it has an active instance of the Dalvik sj that contains the classes required by the applications preJloaded in its address space. fn Android, each application runs its own Dalvik sj. then an application is started, zygote ‘forks’ a child process Ewhich is the app processF; both the zygote and the app processes use the same sj instance until the child does a ‘write’ xmodifies the dataz, in which case a copy of the Dalvik sj is created, for the child. This ensures a faster startJup time for the applications. Thus the zygote becomes the parent for all the applications. b. te can actually check this in the adb shell using the R. This system_server process then starts all the system services. These services run as threads inside the system_server SUoFeVV. 7hLV FDn be veULfied by UunnLnJ Whe IoOOowLnJ command in the adb shell. This command lists the names of the threads running as part of the system_server process.