are Predefined variables really predefined?

Hello, I like to make you guys this stupid questions :-)) here we go: example 1: include "$DOCUMENT_ROOT/file.php" include "$DOCUMENT_ROOT/file.php" include "$DOCUMENT_ROOT/file.php" include "$DOCUMENT_ROOT/file.php" include "$DOCUMENT_ROOT/file.php" example 2: $document_root = $DOCUMENT_ROOT; include "$document_root /file.php" include "$document_root /file.php" include "$document_root /file.php" include "$document_root /file.php" include "$document_root /file.php" Now what I am asking you is to think in microseconds and tell me what is faster? To be precise my question is: are Predefined Variables REALLY Predefined or they do not exist unless you call them? If they don't then calling them twice should make your script slower then assign it's value once to a *normal* variable and use it later all over the script, right? Thanks :-)) P.S: sorry for the gender of the questions , but I was always wondering about it... Maxim Maletsky - maxim@j-door.com <mailto:maxim@j-door.com> Webmaster, J-Door.com / J@pan Inc. LINC Media, Inc. TEL: 03-3499-2175 x 1271 FAX: 03-3499-3109 http://www.j-door.com <http://www.j-door.com/> http://www.japaninc.net <http://www.japaninc.net/> http://www.lincmedia.co.jp <http://www.lincmedia.co.jp/>