Sessions CodeIgniter vs sessions PHP

[eluser]WebbHelp[/eluser]
Hej!

I started with codeIgniter yesterday and I htink it's very nice but I need to learn much in the beginning, and I also think that is the funniest part.

I read the user guide -> sessions, I am not so good at english and maybe I understood it wrong.

When I read the article, I found codeIgniter session as a own created "copy" of PHP session.
I mean, are codeigniter use $_SESSION[]; ?

Or is it a "own" array codeigniter create?

How does session works in CodeIgniter vs PHP $_SESSION

Thanks //WebbHelp