main file services of Linux kernel

Reducing your post made it even worse - and it was terrible to start with.

Read How_To_Ask_a_Question, make some effort to research yourself, then come back with a proper request - and evidence of your own work.

Hello and welcome to the forum

First, please read the information here. Not to sound harsh but this kind of question not only lacks any kind of detail (that could give those helping you a better understanding of what you're needing,) it also sounds more like a demand. "Please" and "thank you" go a long way when asking for help.

Did you perform a Google search before posting? I'm not sure exactly what you mean but I was able find this page, which lists the "important parts of the kernel." Hopefully, that will get you started.

Regards...

Also: the correct answer to an obvious homework(!) question ... ... is not: "Google It.™"

hmm.
somehow i don't think we'll ever see post #2 from this user.