Detail boot procedure in Linux

Question

Describe the detail boot procedure in Linux? Start form Pc on?

Answer 1

Once system is powered on, prime thing will be POST check that means  power on self test.

Then BIOS loads the MBR from the disk into RAM. Then, the BIOS execute the MBR code. Now boot loader record the number of OS installed in to the system. Choose the OS desire to be boot once OS chosen initial RAM disk (temporary root file system) are loaded into memory. While the images are loaded, the boot loader passes control towards the kernel image and the kernel is decompressed and initialized. At this stage, the boot loader check out the system hardware, enumerates linked hardware devices, mounts the root device, and then loads the vital kernel modules. While complete, the primary user-space program (init /sbin/init) starts, that will looks file /etc/inittab to determine the which run level kernel will be boot then it will be check /etc/rc?.d (? means run level got from init tab file)and verifies every script that starts with name S will start in to that level once completed, initrd(temporary root file system) will be unmounted and mount the physical file system and loads the main kernel then login prompt will be obtainable.