What does Compiling / upgrading Linux kernel mean ?

Hey Everyone,

Through this short article i would like to share a concept which most of you might find very trivial , but i myself took sometime to understand it and wanted to share the same if some of you might have felt the same .

Before we proceed lets revise revise four basic concepts very quicky ...

What is an Operating System .. ?

Wikipedia says : The Linux kernel is an operating system kernel used by the Linux family of Unix Like Operating Systems. The Linux kernel was initially conceived and created by Finnish computer science student Linus Torvalds in 1991.

What is a Kernel .. ?

Wikipedia Says : In computing, the 'kernel' is the central component of most computer operating systems it can be thought of as the bridge between application and the actual data processing done at the hardware level. The kernel's responsibilities include managing the system's resources (the communication between hardware and software components).

What is Linux .. ?

Wikipedia Definition : Linux is a generic term referring to Unix-like computer operating systems based on the Linux kernel.

Definition from linux.org : Linux is a free Unix-type operating system originally created by Linus Torvalds with the assistance of developers around the world. Developed under the GNU General Public License , the source code for Linux is freely available to everyone.

What is Linux Kernel .. ?

Wikipedia says : The Linux kernel is an operating system kernel used by the Linux family of Unix Like Operating Systems. The Linux kernel was initially conceived and created by Finnish computer science student Linus Torvalds in 1991.


So from above four question and answers its clear that :

Operating System and Kernel are not the same thing .

So get it clear .... Linux OS and Linux Kernel are not the same thing.

Therefore Ubuntu, fedora , Suse all these are operating Systems based on Linux kernel , started by our friend Linus Torvalds . So when you install any one of these you basically install a full blown Operating System ready to serve you , and this OS internally may be using any Linux Kernel release e.g 2.6.28 or 2.6.30 or .... any other .. they just keep coming with modifications and updates .

Now suppose you have installed a Ubuntu OS on your system with default kernel release 2.6.28 , now after few days you go to www.kernel.org and find the latest kernel release is 2.6.30 , which is ofcourse supposed to be better that 2.6.28 in one or the other aspect.

So now you want to use latest kernel , so now you download the lastest kernel code and " compile that C program code" .

note: to know how to comile kernel code serach web or better look for article written by me : compiling linux kernel 2.6.30

So now after rebooting the system , with new kernel , what difference do you see ....

Practically nothing : Your user name , password are still the same , your wallpaper is still the same , your user setting reamains the same .

Only thing that had changed and is not visible is "Linux Kernel" version , running in background and managing all your resources and processes .

You can check the running version by running following shell command :

$ cat /proc/version

so in the end , just keep in mind Linux based OS and Linux Kernel are two completely different things ... and changing them is also different.

Like you can change your OS from Ubuntu to fedora and both of the may still be using same Linux Kernel 2.6.30 .

Thanx for reading .