How does Archive.php gets parameters / creates correct page

Hello,

can anybody please explain to me, how the process of archive.php building the specific correct page works.

If i use link http://www.XXX.com/?m=200805 the archive.php page gets created with the correct posts / header for May 2008 in this case.

I understand that the “is_month” function gives back true if this is a monthly archive page. But where reads the archive.php the m_200805 in resp where is the overall function that recognizes upon calling a link like “www.XXX.com/?m=200805” that this is supposed to be a archive page for the resp month and therefore calls archive.php, transfers the value of 200805 and gets only the according posts?

Hope anybody can clarify this to me! Thanks!

Cheers
Florian