The initialization manager is an important part of the root filesystem. It is the first thing the kernel executes, and it has the responsibility to start the rest of the system.
This recipe will introduce the sysvinit initialization manager.
This is the default initialization manager in Yocto and it has been used in Linux since the operating system's origin. The kernel is passed an init command-line argument, typically /sbin/init, which is then launched. This init process has PID 1 and is the parent of all processes. The init process can either be implemented by BusyBox or be an independent program installed with the sysvinit package. Both of them work in the same way, based on the concept of
runlevel, a machine state that defines which processes to run.
The init process will read an inittab file and look for a default runlevel. The default inittab file is installed with the sysvinit-inittab package and is as follows:
# /etc/inittab: init...
