The Core Animation component, alongside the PowerGL hardware component (the iPhone 3GS uses OpenGL ES 2.0), it is responsible for the device's animated graphics. The iOS needs less than 1 gigabyte when it comes to storage, and supports future applications from Apple, as well as from third-party developers. It also supports bundled applications. The software cannot be directly copied from MAC OS X to the iPhone, but must be first written and compiled specifically for the iOS. Such as the iPod (a multi touch screen based portable media player which is also developed by Apple) , the iPhone is managed by iTunes (a manager software also developed by Apple). Earlier versions of the iOS required model 7.3 or later of the iTunes, which supported MAC OS X 10.4.10 Tiger or later, and 32-bit Windows XP and Vista.
Apple supports iOS, and several updates are made available via iTunes. These updates are usually for fixing bugs or adding new content to the already existing one.A major iOS update is released alongside a new model of the Apple iPhone (the iOS 2.0 was released at the same time with the second generation iPhone 3G, the iOS 3.0 was released alongside the third generation iPhone 3GS, and the iOS 4.0 was released at the sime time with iPhone 4 in 2010) . A new iOS update usually requires a newer model of the iTunes, such as th 3.0 update required iTunes 8.2, but the iTunes requirements did not change. These updates include both new features and security patches. For example, user experienced a problem with the iPhone 3G regarding dropped calls. This problem was fixed by releasing a new iOS software update.
Most of the device's control is built around the home screen. The home screen is a list of all available applications. The first three models of the iPhone supported only one program running at a time, but with the release of the new iPhone 4, users can now open several applications at the same time, even tough most functionality is available during calls or when music is playing. The home screen even has a dedicated button(the only physical button on the front side of the device, situated under the LCD screen). By pressing it, the current application is closed and users are redirected to the Home screen menu where they can select another application.