5 ways Apple's iPhone OS 4 is a game changer

Computerworld - Less than a week after launching the iPad, Apple teased iPhone users -- as well as iPod Touch and iPad users -- on Thursday by previewing some of the features in the next iteration of the iPhone operating system. The update, due out this summer for the iPhone and iPod Touch and in the fall for the iPad, packs a lot of punch for developers, who get access to 1,500 new APIs and iPhone/iPad features previously accessible only by Apple itself.

For users, Apple promises more than 100 new features, several of which the company showed off at its iPhone OS 4.0 event.

While CEO Steve Jobs chose to highlight seven features -- he called them the "tent poles" for the upcoming update -- I want to focus on the five new features that will be game changers for Apple and for the mobile industry as a whole.

1. Multitasking and other developer enhancements

The single most-requested iPhone feature since Apple opened the platform to third-party developers two years ago has been the ability to run multiple apps at once and to allow apps running in the background to continue to access network and Internet resources.

For two years, Apple has stuck to its no-multitasking and no-background-apps stance, with the exception of some of the company's own built-in iPhone apps. The mantra from Apple has been simple: Multitasking and background apps slow the overall performance of the device and drain the battery faster.

In delivering multitasking to the masses of iPhone developers, Apple didn't simply decide to let all apps run and perform all their functions simultaneously, which is what most other platforms do. Instead, the company looked at the types of functions background apps need and created services that give multitasking apps access to those core needs.

This allows basic processes like playing music, updating your location and completing tasks to work when a user switches apps. This tack is smart because when most apps are running in the background, you rarely interact with most of their features -- so why take up resources that can be allocated elsewhere?

To that end, Apple offers developers seven services: playing audio; access to VoIP features (so you can talk while using other apps); updating location data (where Apple cleverly relies on GPS -- a resource and battery hog -- only when the device switches between cell towers); enhanced push notifications.; app-generated notifications (such as a to-do list from a project management app); autocompletion of in-process tasks like uploading or downloading data after a user switches apps; and fast switching between applications.

That last one allows the device to automatically save an app's current state and any open data when switching -- via a dock-like list of running apps -- to another task.