iOS 5 Multitasking Shown On Video; Makes Things Clearer

Few days ago, we posted a nice article on how the iOS multitasking bar really works, and we tried to clear the big confusion caused by it. It was based on a developers blog post, which went on to cause a lot of uproar on the Internet. A lot of people believed, that killing the apps in the multitasking bar saves battery and clears up RAM. However, according to a recent video uploaded by the same developer, that’s not how it works and it’s not how we thought it worked.

The developers at Apple are really smart and they’ve applied their smartness to the multitasking bar. It turns out, that when you launch an app, a lot of things start happening. If you launch an app that isn’t doing any work in the foreground and background it, the app will still be running in the background, but it will not be using any CPU as it will be suspended immediately. It will still be using some memory, but this ensures that you get back to whatever you were doing on that app. When you kill the app, the memory being used by that app is indeed freed, but then you can’t get back to what you were doing. So that’s the whole point, killing an app in the background does free up memory, but doesn’t affect the CPU percentage or battery life.

The case is different, when you background a running app that is doing some work such as downloading a file, playing music, transferring files etc. In this case, as soon as the app is in the background, it isn’t suspended immediately and continues to use memory and CPU till the work is completed. Once the work is completed, the app will be suspended and the CPU usage goes down to zero, but memory is still being used. There are a few more states, of which you’ll learn in the video below.

We would really suggest that you watch all the 16 minutes of this awesome demonstration video, which actually clears up all the confusion. If you’re an Apple user, you should be proud of how smart iOS is and how it manages RAM and CPU for processes. Let us know in the comments, your thoughts and opinions about this and whether or not you got it.

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  • willhains

    How did you manage to get Instruments to record all processes? When I try, the Record button is disabled. There seems to be a “Step 0″ missing here…