iOS (formerly: iPhone OS) is an operating system used in Apple Inc.'s mobile phone. When Steve Jobs thought of making an iPhone, he had two options, first to make Mac smaller or to make the iPod bigger. He met the Mac and iPod team and after that it was decided to make an iPhone OS. Along with this, it was successful in providing a platform for other developers too. At the same time, it proved to be good for those Mac developers, because they started making applications for the iPhone as well.