A man and his 16-year-old daughter were traveling through Seattle on their way back from a long hiking trip in Alaska's Denali National Park. During the entire trip, the man had to live with the horrible, plastic taste of cheap instant coffee. Still, he put up with it because he enjoyed the extra caffeine boost that allowed him to keep up with his daughter. While in Seattle, the man remembered the lore about the Emerald City's espresso habits. With espresso carts on every street, he didn't have any trouble finding one quickly. As he ordered a latte, he knew darn well that the tasty caffeine bomb would give him the jitters, but he really wanted one nonetheless. He would have enjoyed it too, had his daughter not asked a simple but probing question, one that would change pleasure to guilt and for which he had no answer. She asked with a menacing stare, "What exactly does that do for you?"
If after reading the previous section you feel that your particular development efforts won't involve component-based applications, you may still want to ask the same question: "What does OLE's Compound Files technology do for me?" In a manner of speaking, compound files give you the energy boost of caffeine without the jitters. While you are not required to indulge, there are certainly benefits to starting the habit, so to speak. Let's explore this in the context of how we might add file I/O capabilities to the Patron sample, which prior to this point has none.