OS X Mountain Lion Bible

Understanding the Desktop

Apple popularized a graphical user interface (GUI) with a desktop metaphor with its famous Macintosh line, introduced in 1984. As Microsoft followed suit with Windows, it made the desktop metaphor common parlance throughout the world.

The desktop metaphor is the concept of the screen on the monitor acting as a visual representation of your physical desk. In this sense, the desktop contains folders (which are virtual representations of cardboard folders or drawers), documents (which are virtual pieces of paper), a trash can to dispose of items, and other visual icons designed to imitate real-life objects.

Despite being based on a commonplace metaphor, the desktop used in OS X has many features and functions that may not be immediately apparent.

In essence, the desktop is the background on the screen—the expanse of space that sits behind the Dock and below the menu bar, or its canvas. By default, every version of OS X has featured a different background image signifying which version of OS X is running.

New Feature

OS X Mountain Lion uses a photo of a yellowish unnamed galaxy as its default desktop background image, not the reddish Andromeda galaxy of OS X Lion or the stellar auroras of Mac OS X Leopard and Snow Leopard.

But the arrangement of the default disk icons has not changed: The startup disk appears at the upper right of the desktop, and any additional disks' icons appear below the startup disk's icon. (If you don't see the disk icons, choose Finder⇒Preferences ...