What does multitasking mean for the iPhone 4S

Factual Questions
1

The iPhone 4S has multitasking, and Napier has the iPhone 4S. But what does multitasking mean, in this case?

There are lots of statements out there on the web to the effect that those apps running in the background, which is only possible because of the multitasking, are drawing power and causing the poor battery life problem now in the news. Is this really accurate?

I can see apps nominally still open in the background by double clicking the home button, but in this case, being open does not mean consuming any processor cycles or other resources that use more power, does it? At least not for most apps.

One example that WOULD use power is listening to music while doing other things. I’m not sure whether there are any other examples. Perhaps if Reminders is using the GPS to keep checking location because you have set a reminder to go off when you reach home, that would be an example. Are there others?

Because I’m thinking that with a very tiny few exceptions, an app “running in the background” is only occupying a bit of memory and retaining its state as of when the user last closed it, and not using electrical power. Is this right?

Can anybody shed more light on this?

2

Multitasking has been available on many iphone and ipod models since the release of iOS 4, well over a year ago. The recent battery life issues of the iPhone 4S seem to be related to a bug in iOS5. Apple cited iOS 5 specifically, so its unclear if this problem only affects the iphone 4s or all iOS devices.

In general, multitasking does use battery power faster then not. Apple designed the multitasking capabilities of iOS around the idea of preserving battery life. You are correct in assuming that background apps are paused and don’t use processor cycles like the active app. Apple designed the multitasking APIs to allow apps to behave like they truly are running in the background, so there is still some loss of battery life (and performance) while having apps open but inactive.

You are also correct that using the location services uses more battery power. The same is true for wifi and blue tooth connectivity, even if you are not actively using those features. I believe this is true for all phones, not just the iPhone, but I can’t cite this. (I’l find cites for anything else I stated if you need them, but I’m too tired right now).