From: "Paul Koning" <pkoning at equallogic.com> Dwight> ---snip--- The first sentence in Dwight> Hi Interesting! I've always considered order of execution to Dwight> be one of the fundamentals of being able to predict what a Dwight> computer does. I've always thought of it as an accentual part Dwight> of programming with predictable results. That's true for a single CPU sequential computer without any interrupts going on. It isn't true if you run things in parallel on several CPUs. It may not be true in multi-issue computer (which is most modern fast CPUs) if the architecture has sufficiently relaxed ordering rules. But all that applies to the hardware. Many programming languages don't specify a single order of doing everything in every possible program, but instead leave things partially unspecified, so the translation from source code to machine language has more opportunities for optimization. So even if a machine is fully sequential and fully ordered, the high level language programs you feed it might not be. paul