I have a very naive question here, and I would like you to correct me on whatever wrong concepts I put out here. The question is as follows:

I have ubuntu installed on my machine, now I write a helloWorld.c program in C language. Now, on the operating system I have a compiler installed, when I execute my helloWorld.c program, the OS schedules the compiler and that basically compiles my code into machine code, which eventually, I execute.

Now my kernel code is written in C, then how does my machine interprets that code? Say my kernel code is helloWorld.c, now would not I require any compiler, to compile this code. Also, if I hardcode a compiler in maybe ROM or something, then what language is it written in? Assembly language?

Let me know if I have made myself clear with the problem.

Thanks.

EDIT: By kernel code I mean, the code for operating system. Operating System code. I guess it is written in C right?