"I know this man is going to be here at 6 p.m., order a hot dog, a hamburger, fries, and then cheesecake," the waiter thinks on the third night. Why don't I prepare these products ahead of time and surprise him with them? Perhaps I'll get a large tip." So you walk into the restaurant, order a hot dog, and the waiter places it on your dish right away! The hot dog is then finished, and just as you're ready to order the hamburger, the server places one on your plate. The rest of the dinner proceeds in the same manner, with you eating the entire meal in four seconds increments and never having to wait for the kitchen to produce the food. Because of your waiter's intelligence and attention, your whole eating experience this time consists entirely of eating, with no waiting for food to be made.

This example describes the function of the processor's L1 cache. The L1 cache is a table on which one or more plates of food can be placed. In the absence of a waiter, the table serves as a basic food buffer. You can eat till the buffer is empty while it's stocked, but nobody appears to be refilling it intelligently. The cache controller is the waiter, who takes action and adds intelligence to select which meals should be placed on the table in advance before you need them. He utilizes his expertise to practical estimate which food you will demand next, much like a real cache controller, and if he guesses properly, you will never have to wait.

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