Foreground-background is a scheduling algorithm that is used to control execution of multiple processes on a single processor. It is based on two waiting lists, the first one is called foreground because this is the one in which all processes initially enter, and the second one is called background because all processes, after using all of their execution time in foreground, are moved to background.
When a process becomes ready it begins its execution in foreground immediately, forcing the processor to give up execution of current process in the background and execute newly created process for a predefined period.
Note: Windows Phone apps are made dormant state when running in the background or when the phone is locked (to conserve device memory and battery life). If your application needs to perform processing when it is (may be) in the background you can use a background agent
