1 Start Computer
2 BIOS search boot program from hard disk
3 Run GRUB loader(grub menu will list the systems for you to choose)
4 Grub load linux kernel
5 Run program : init
6 Run system initializing scripts(in /etc/rcS.d)
7 Run numberred initializing scripts(in /etc/rcX.d, X is the run level number, default is 2, scripts are links to /etc/init.d)
