#### 1.3.1 Screens and Heads ¶

A screen is an Xlib concept representing a section of video memory onto which physical monitors, called “heads”, are mapped. A screen can be thought of as an abstract rectangle containing all the heads arranged in a particular layout.

With most modern systems, you’ll only have a single screen no matter how many heads are connected to your computer. Each head will have its own frame, and you can move between heads using the normal frame movement commands.

The layout of the heads within the screen can be specified in one of two ways: either at startup using your system’s Xorg configuration files, or on the fly using tools like XRandR. If the computer is booted with multiple monitors attached, but without specifying a layout for them, they will all show identical output.

StumpWM will attempt to detect the layout of the heads once at startup, or any time a RandR command is issued.

In rarer setups you may have multiple screens, with one head per screen. That means that you’ll move between heads using screen movement commands (‘snext’, ‘sprev’, and ‘sother’) rather than frame movement commands.