0.1.2 What Is the User Interface?

The basic user interface is usually understood to include things like menus, windows, the keyboard, the mouse, the "beeps" and other sounds the computer makes, and in general, all the information channels that allow the user and the computer to communicate.

Of course, using a modern computer system also involves reading manuals, calling help lines, attending training classes, asking questions of colleagues, and trying to puzzle out how software operates. A successful computer system or software package supports those activities, so that support is part of the user interface too.

But in a sense, all of these parts are the "peanut butter" we mentioned in the previous section. No matter how well they are crafted, the interface will be a failure if the underlying system doesn't do what the user needs, in a way that the user finds appropriate. In other words, the system has to match the users' tasks. That's why the book's central message is the need for "task-centered" design, and that's why the design of the user interface can't be separated from the design of the rest of the system.