Read original post at Anything about WinRT Blog
As explained in Reclaiming memory from Metro style apps, Windows 8 optimizes the way RAM is dedicated to running processes. Metro Apps are even more impacted than just reclaiming memory from their working set because the system can decide to simply terminate the suspended ones when low memory conditions are detected. It is important to take care of this scenario when you write your code so the user, who is unaware of the App termination expects to get back where he was when he clicks on its tile: this is part of the PLM (= Process Lifecycle Management) and I’ll spend some time describing the basics before returning to the hidden termination case.