iOS

iOS is Apple’s proprietary operating system that runs on the iPhone, iPod Touch, and iPad. Built for multitouch interaction, all user input in iOS is through touch gesturing, a technology that Apple has pioneered. Through the use of actions such as swiping, pulling, pinching, and tapping, users are put in a fluid, intuitive landscape. Many of Apple’s devices house gyroscopes and accelerometers, which allows users to change the orientation of applications as well as directly control by simply tilting the devices.

Mac OS X acts as the parent software for iOS, as it shares the Darwin operating system foundation, making it characteristically a UNIX operating system. There are four abstraction layers, ways of hiding the implementation details of a particular set of functionality, within iOS: the Core OS layer, Core Services layer, the Media layer, and the Cocoa Touch layer.

The overall trend of the operating system has given greater control to developers. There was no SDK (software development kit) for building native apps until iPhone OS 2.0, and at that point it was rather limited. iPhone OS 3.0 saw tremendous improvements, giving developers new abilities such as Core Location and Push Notifications. Finally, iOS 4.0 saw the introduction of multitasking, though in practice it asks more like app switching.