Exploring the Execution Model

The execution model of Windows Phone is designed to make the phone as responsive as possible and to maximize the battery life of the device. One way that this is achieved is by limiting the phone to a single running application. Multiple applications running in the background risk slowing the foreground application and may tie up the processor and cause the phone to consume more power.

In addition to greater responsiveness and extended battery life, the execution model provides users with a consistent navigation experience between applications. On Windows Phone, users are able to launch applications from the App List screen or from a tile on the Start Experience. The hardware Back button allows users to navigate backward, through the pages of a running application or through the stack of previously running applications.

The goal of transient state preservation and restoration is to provide the user with a simulated multiple application experience, where it seems to the user that your application was left running in the background, even though it may have been terminated by the operating system.