The Dock: The Mac's All-Purpose Application Launcher

The Dock as shown in OS X El Capitan
Screen shot courtesy of Coyote Moon, Inc.

The Dock is a ribbon of icons that normally spans the bottom of the Mac desktop. The Dock’s main purpose is to serve as an easy way to launch your favorite apps; it also provides an easy way to switch between running apps.

The Dock's Main Function

The Dock serves several purposes. You can launch an application from its icon in the Dock, check the Dock to see which applications are currently active, click a file or folder icon in the Dock to reopen any windows that you minimized and add icons to the Dock for easy access to your favorite applications, folders, and files.

Applications and Documents

The Dock has two main sections, which are separated by a small vertical line or a 3D representation of a crosswalk, depending on which version of OS X you're using.

Icons to the left of the divider hold programs that Apple populates with a collection of apps included with OS X, starting with the Finder, and including such favorites as Launchpad, Mission Control, Mail, Safari, iTunes, Contacts, Calendar, Reminders, System Preferences, and many others. You can add apps, as well as rearrange the app icons in the Dock, or remove the icons of unused apps at any time.

Icons to the right of the divider represent minimized windows, documents, and folders.

Minimized windows stored in the Dock are dynamic; that is, they appear when you open a document or app and choose to minimize it, and then disappear when you close the document or app or choose to maximize the window.

The right-hand Dock area can also hold frequently used documents, folders, and stacks, on a non-dynamic basis. In other words, unlike minimized windows, documents, folders, and stacks don't disappear from the Dock unless you choose to delete them.

Stacks in the Dock

At their most basic, stacks are simply folders; you could drag a folder you often use to the right-hand side of the Dock, and OS X will be kind enough to turn it into a stack.

A stack is a folder that has been placed in the Dock which allows the Dock to apply special viewing controls. Click a stack and the content springs from the folder in a Fan, Grid, or List display, depending on how you set your preferences.

The Dock comes prepopulated with a Downloads stack that shows you all the files you have downloaded from the Internet using your favorite browser. You can add stacks by dragging favorite folders to the Dock.

Trash in the Dock

The last icon found in the Dock is neither an app nor a document. It’s the trash, that special place to which you drag files and folders so they can be erased from your Mac. This icon can't be removed from the Dock, nor can it be moved to a different spot in the Dock.

Dock History

The Dock first made its appearance in OpenStep and NextStep, the operating systems that ran NeXT computer systems. NeXT was the computer company that Steve Jobs created after his original departure from Apple.

The Dock was then a vertical tile of icons, each representing a frequently used program. The Dock served as an application launcher.

Once Apple purchased NeXT, it gained not only Steve Jobs but the NeXT operating system, which served as a basis for many of the features in OS X, including the Dock.

The Dock’s look and feel have undergone quite a metamorphosis since the original version, which appeared in the first OS X Public Beta (Puma), starting out as a 2D plain white strip of icons, changing to 3D with OS X Leopard, and returning to 2D with OS X Yosemite.