Whenever PC is turned ON, BIOS takes the control, and it performs a lot of operations. It checks the Hardware, Ports etc and finally it loads the MBR program into memory (RAM).
Now, MBR takes control of the booting process. Functions of MBR, when there is only one OS is installed in the system are as given below:-
The boot process starts by executing code in the first sector of the disk, MBR.
The MBR looks over the partition table to find the Active Partition.
Control is passed to that partition's boot record (PBR) to continue booting.
The PBR locates the system-specific boot files (such as WinXP ntoskrnl).
Then these boot files continue the process of loading and initializing the rest of the OS.But , whenever there are multiple OSes, be it multiple Windows or Windows with Linux, then Boot process will be slightly different.
I think that you definitely need to read the following article:
How to develop your own Boot Loader
It just highlights some interesting points for you.
This article for those who have been always interested in the way the different things work. It is for those developers who usually create their applications in high-level languages such as C/C++, but faced with the necessity to develop something at low-level. This article about low-level programming on the example of working at system loading.
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