iOS system hierarchy

This article turns from: http://blog.csdn.net/lxl_815520/article/details/51172917, overview

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. Understanding the system architecture of iOS is a great help for our daily development. iOS is UNIX-based, so we can trust this operating system, knowing that it is much better than other operating systems from the stability of the system.

Second, the iOS OS hierarchy and related frameworks

1. Core OS Kernel layer: Contains accelerate framework, External accessory Framework, Security framework, system and several frameworks, basic C-based interface
2. Core Services: Includes Address Book framework, Cfnetwork Framework, core Data framework, core Foundation framework, Core Location framework, core Media framework, Core Telephony framework, Event Kit Framework, Foundation Framework, Mobile Core Services Framework, Quick look Framework, Store Kit Framework, System Configuration Framework, Block Objects, Grand Central Dispatch, in Apps Purchase, location Services, SQLite, XML support and other frameworks, are basically based on the C language interface.
3. Mediah Media layer: Includes core Graphics, Core Animation, OpenGL ES, Core Text, Image I/O, Assets Library Framework, Media Player Framework, AV Foundation, OpenAL, Core Audio frameworks, Av Foundation, Core Media, and more
4. Cocoa Touch layer: Includes Address Book UI framework, Event Kit UI Framework, Game Kit Framework, IAD Framework, MAP kit framework, Me Ssage UI Framework, UIKit framework, etc., this layer is basically a objective-c-based interface

iOS system hierarchy