Session - System Resources

Hi,
We are using Oracle 9iAS portal, just curious to know :

1.) We have porlet which is JSP application, and as I know every porlet have their own session timeout, either PL/SQL portlet or portlet in JSP application. If I set the Session Potlet for entire Portal level is 30 minutes, and portlet level is 40 minutes, does it means that the entire portal will timeout after 30 minutes????


2.) When we talk about session load the system resources, beside the mamory used, what are the others resources it means????
pls advice....