The iOS operating system is owned, developed, and distributed by Apple. iOS was released in 2007 originally for the iPhone and iPod Touch, and has been extended to support other Apple devices such as the iPad and Apple TV. iOS can only be used on Apple-produced hardware and is not licensed for installation on other hardware. iOS is derived from OS X and is also seen as Apple’s mobile version of the OS X operating system used on Apple computers.
The user interface of iOS is based on the concept of direct manipulation, using touch gestures rather than a mouse. Interface control elements consist of sliders, switches, and buttons. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the iOS operating system and its multitouch interface. Internal accelerometers are used by some applications to respond to shaking the device (one common result is the undo command) or rotating it in three dimensions (one common result is switching from portrait to landscape mode).
