Glahrrgh... Sessions...

How is the session data handled when using the PHP module? Are all the registered variables stored in memory so that when one script changes it, a concurrent script gets the new value when accessing it? Let's say we have a frameset of three frames, all frames perform a check to see whether a variable is set, if not, they perform some really heavy functions to get it set. Using the "CGI" there's a fairly good chance that all three scripts needs to set the variable (presuming the variables are loaded at startup, and dumped at the end of the call). Is this the same case with the module, or is it like a working application server?