Linux Distribution Step By Step Booting Process | /etc/grub/grub.conf /etc/fstab

While we switch on the Linux System. It will perform the following Boot process
BIOS-MBR-BOOT LOADERKernel-Init -Run Level
1) BIOS it will load the MBR into the Memory From the Boot Sector ( Boot sector it will be floppy ,Hard Disk , Cdrom. These Boot load priority it will be change from the BIOS Setup)

2)Then Boot Loader It will take the control of the system From the following file /etc/lilo.conf /etc/grub.conf (LILO is most Linux Distribution Default Boot Loader) [ linux it will load the image windows it will load the Dos].Details about /etc/grub.conf file Refer This Link.

3)It will show the list of Operating System which one need to boot. It will identify which kernel needs to boot. 

System Startub 
Linux Loads the kernel & initrd(initial RAM disk) image into system memory to boot the system .
4)Then Kernel run init (initialization) program according to the /etc/inittab.
Under the /etc/inittab file it has Run level script 
Example : /etc/rc.d/rc0.d
Just like it has the Linux Six Run level
Under the run level 
If File start With
K-Shutdown Script
S-Start Up Script
5)Based on the default run level it will executed the process.Study about Run Level Refer these Link
Important files For Linux Boot Sequence
Boot loader
/etc/grub/grub.conf
/etc/lilo.conf
System Instillation it will refer to the the Mount partition table from the /etc/fstab file
Run level it will refers to the /etc/inittab file

Related post