Here I'm gonna tell you how Linux works From the beginning to the end Step 1: The bootloader Your Firmware opens an app called bootloader (usually in Linux it's grub) then the bootloader uses its config to load the kernel Step 2: the kernel After the kernel is loaded it knows where is your root partition it mounts it as / then runs /sbin/init in most distros /sbin/init is systemd Step 3: the init After the kernel runs the init the init starts the services and listens to shutdown or reboot signals (killing the init makes the kernel panick)