iOS 4 Multitasking - Daemon Process

How to create an app that functions like开发者_JS百科 demon process at the background?

Is this possible?

Generally not. Apps can't fork processes, the only thing you can do is ask for some time (max 10 minutes) to resume tasks after your app was send to background. For specific use cases (audio playing, location tracking, VOIP) there are well defined exceptions to this rule.

No. Apple only allows specific hooks for background functions, but you cannot - without jailbreaking the device - run anything in the background "generically".

Better think of Multitasking as fast-app-switching with some extras. I recently did a little writeup of this on my blog trying to shed some light on a topic in the Apple discussion forums.

Maybe you find it useful to understand more of the backgrounds. It can be found here: http://www.danielschneller.com/2010/11/ios-421-battery-drain-on-ipad.html