High Quality Content by WIKIPEDIA articles! iOS (formerly known as iPhone OS) is Apple`s mobile operating system. Originally developed for the iPhone, it has since been extended to support other Apple, Inc. devices such as the iPod Touch, iPad, and Apple TV. Apple, Inc. does not license iOS for installation on third-party hardware. As of October 4, 2011 (2011 -10-04), Apple, Inc.`s App Store contained more than 500,000 iOS applications, which have collectively been downloaded more than 18 billion times. It had a 26% share of the smartphone operating system units sold in the last quarter of 2010, behind both Google`s Android and Nokia`s Symbian. In May 2010 in the USA, it accounted for 59% of mobile web data consumption (including use on both the iPod Touch and the iPad).