iPhone OS 4.0 анонсирована!

что в ней появится - можно прочитать на каждом заборе,
а вот тот факт что SDK и прошивки уже доступны для девелоперов не радовать не может!

Multitasking

In iPhone OS 4.0 and later, applications can perform tasks while running in the background. When the user quits an application, instead of its process being terminated, the application is moved to the background. Shortly after moving to the background, most applications are suspended so that they do not run and consume additional power. However, applications that need to continue running can ask the system for the execution time to do so.

Regardless of whether an application is running in the background or suspended, the fact that the application is still in memory means that relaunching the application takes much less time. An application’s objects (including its windows and views) normally remain in memory and therefore do not need to be recreated when the application is subsequently relaunched by the user. However, if memory becomes constrained, the system may purge background applications to make more room for the foreground application. To appear consistent with the application remaining in the background at all times, an application should store information about its current state when it moves to the background and be able to restore itself to that state upon a subsequent relaunch.