shared memory

Hello, I've recently started PHP development after a few years of working with ASP. So far I really like PHP, but am having trouble using some of the techniques I had in ASP. For example, I really like using ASP's Application object to cache data in, but I can't seem to have an equivalent in PHP. (Due note that I'm also new to the Unix/Linux environment, so if I have any concepts glaringly wrong, please correct me). I've read over the System V shared memory functions, but I can't tell if these would accomplish what I'm looking to do? I guess what I really need to learn is how threading and synchronization works in Apache/PHP. I had just mastered COM/ASP's single-thread/multi-threaded design and could write shared, multi-threaded ATL components that all the ASP pages could read from marshalling and all that. Are there any good resources/docs on the type of architecture PHP uses and how to accomplish the above in the Apache/PHP environment? I've looked around at some books, but all I can find is basic here's-how-to-do-a-web-page type stuff. Ideally what I'd like would be an object that would stay loaded in memory (in-process) so that PHP scripts could call functions and variables against it with minimal overhead (specifically an object that could cache query results instead of each page requerying the database). Is such a thing possible? Or do I have to move over to Servlets/JSP to find this functionality? Thanks! - Stephen