What really happens behind the screen when we power on the monster. (x86) Lets go through the overview!
1. BIOS (Basic Input output System) intializes the hardware and tests the main hardware. This process is also called POST ( Power on Self Test). After this the OS takes over.
2. Bootloader comes into the picture which is usually stored in the boot sector in the hard disk. For linux, boot loader will install kernel image and initial RAM-based file sys into memory so it can be used directly by the kernel.
3.When the kernel is loaded in RAM it configures not only compture's memory but also all the hardware attached to the system. initramfs performs all the actions needed to mount proper root filesystem (FS) and drivers.
4.Mount program tells OS that FS is in place. If this is successful then initramfs is cleared from the RAM and init program is executed /sbin/init
5.Init starts other process and gets the system up and running. Except for kernel proceses most of the other processes find their origin ultimately to init. Init is not only used to start up the system but also to shut it down cleanly.
6. By the end of the boot process init start a number of text-mode login prompts.
7.X Window System is usually the final step in the boot process. In my system I found Xorg rather than xserver.
