LINUX SYSTEM INITIALIZATION

DEBIAN

1.BIOS
   |--- POST (Power On Self Test)
    `--- Load initial code (bootloader code/kernel code...etc) form DISK
2.Bootloader (Bootstrap Loader)
    `--- load system kernel image and initrd image, hands over control
`-- Linux kernel             `---- initramfs
    * initrd : image of temporary root file system loaded into memory
               do hardware detection,module loading, mnt root file sys
3. initrd (mini-Debian System (Started by bootloader))
`----- /init is executed
4. Debian-System
|----- 0. /sbin/init (init(8)) is executed
| |--- parent of all processes
| `--- create process from script /etc/inittab
|----- 1. System goes into runlevel N(none) by following /etc/inittab
|----- 2. System goes into runlevel S for initialization
`----- 3. System goes into runlevel 2-5(multi-user))(determined by /etc/inittab)
`-- rc.local is executed at the end of each multiuser runlevel

A Bootable Linux Image

Load Sequence: Boot Loader->kernel->initrd->rootfs(the fs user will be working on)