SDL questions.

My first question is, when I use this function SDL_Init(WHATEVER), where does the information go?
Secondly what exactly happens when I lock a surface, in other words I want to know what kind of information is
stored in the SDL_LockSurface() function. It would really appreciate if someone could find some time to
answer my questions. :)

I don't know the exact answers to your questions and I can't really comprehend why you would need to know unless you were compiling your own version of SDL. Have you read the docs on these functions?

Yes I've read the docs but it didn't really answer my questions. It's not like i'm compiling my own version of SDL or something.
I just like to know what is really going on when I write a program, it just feels better to know how it works and not just that it's necessary to use the functions for whatever reason.
EDIT: The docs tell what the functions do but not what a lock is technically.

if you really want to know how its implemented, download the code and take a look, mind you it may well be overly complicated too you, so don't expect it to suddenly click when you read it.

Edit: check here as well, might have something usefull
http://www.libsdl.org/cgi/docwiki.cgi/SDL_5fLockSurface