Most architectures support cheap sp -based addressing. Good locality for VM systems, caches. Lisp, ML, many interpreted languages need heap for activation records, which have non-nested lifetimes. Procedures and Activations A procedure definition associates a name with a procedure body and associated formal parameters . Procedure f is recursive if two or more activations of f are nested .
Execution corresponds to depth-first traversal of tree.
The lifetime of an activation record corresponds to the longest lifetime of anything contained in it. For most conventional languages, including C, Pascal, PCAT, etc., the lifetimes of local data are also contained within the activation 's lifetime. Thus, since activation lifetimes behave in a stack-like manner, we can allocate and deallocate activation records on a stack . Sequence of steps that, taken together, build and destroy activation records. Entry sequence - performed by callee.