The heart of a mobile device is its operating system, which governs its built-in computing power as well as applications, services like e-mail, and cellular-network features such as visual voice mail. Competition among operating systems will thus shape the future of mobile technology. And because those systems can also allow control of laptops, Web TV devices, and more, they may well become the brains controlling most consumer electronics.

The main OS technology battle pits Apple’s proprietary operating system, iOS, against Google’s mostly open-source Android system. But smaller competitors are growing quickly, including Hewlett-Packard’s WebOS, the BlackBerry OS, and Windows Phone 7, now to be used by Nokia under a new partnership arrangement with Microsoft.

Apple’s iOS—which first appeared on the iPhone and now extends to the iPad tablet and the iPod Touch—is designed to maintain tight control over what users can do with a device. It also requires them to deal with Apple’s App Store.

But given the competition that’s arisen, concerns that Apple’s closed approach would stifle innovation were unfounded, says Gerald Faulhaber, a professor emeritus of business and public policy at the Wharton School, who researches mobile-device markets. “There is plenty of evidence of competition, and the market for operating systems is robust,” he says. And this, he says, will drive development of new ideas and get new technology into consumers’ hands.

What’s more, the competitive market for apps—the most popular of which are available on all major operating systems—ensures that the penalties for switching from one device or operating system to another will remain low, Faulhaber says.

All the manufacturers are working toward making such switching easier. For example, HP’s WebOS makes use of short-range wireless connections, allowing users to tap devices together to make one open a Web page being viewed on another. That technique can be extended to photo sharing and other data exchange.

Other manufacturers are working on similar strategies for sharing data and applications. “What users want and need is for all their devices to be connected naturally together,” says Jon Rubinstein, a creator of the iPod and head of HP’s line of WebOS mobile devices, which the company acquired when it bought Palm in 2010. “A mobile ecosystem should really be able to give you a great user experience anywhere, whatever you are doing.”

Beyond making such interoperability possible, mobile operating systems could come to dominate all forms of computing. ­Rubinstein plans to bring WebOS to HP’s printers and laptops. And Apple’s forthcoming desktop and laptop operating system, OS X Lion, borrows interface features from iOS. Google and Apple have also installed versions of their mobile operating systems in their Web TV devices.