"ios" System framework Learning

The system architecture of iOS is divided into four tiers : The core OS layer, the core service layer, the media layer, and the Cocoa touch layer.

Core OS: the bottom layer of the iOS system architecture is the kernel OS layer, which includes memory management, file systems, power management, and some other operating system tasks. It can interact directly with the hardware device.

Core Services: The second tier is the central service layer, which we can use to access some of the iOS services.

Media: The third layer is the medium layer, through which we can use a variety of media files in the application, for audio and video recording, graphic drawing, as well as the production of basic animation effect.

Cocoa Touch: The topmost layer is a touch layer, which provides a variety of useful frameworks for our application development, and most of it is about the user interface, which is essentially responsible for the user's touch interaction on the iOS device.

Many of the technologies in the Cocoa Touch layer are based on the Objective-c language. The Objective-c language provides support for iOS like collections, file management, network operations, and more. Like the uikit framework , it provides a variety of visual components for applications such as window, view, and button components (UIButton). Other frameworks in the Cocoa touch layer are also useful for our development in the application, such as access to the user's correspondence function framework, the framework for obtaining photo information, and the hardware support for the accelerometer and the three-dimensional gyroscope.

The most important thing for an app developer is the cocoa touch framework.

is a comparison chart of Mac OS and IOS system architectures:

As an application developer, although it is not uncommon to touch cocoa touch with the layers below cocoa, it is necessary to understand their role. The above iOS system framework and Android have a lot in common with http://blog.csdn.net/xn4545945/article/details/7761417,Android open source, iOS closed sources.

More information:

Http://www.cnblogs.com/zhangmangyuan/archive/2013/03/28/iOS.html

Http://www.kejixun.com/article/201308/17085.html