????1??Core OS ?????????Accelerate Framework??External Accessory Framework??Security Framework??System????????????????????c???????
????2??Core Services????????????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 App Purchase??Location Services??SQLite??XML Support???Щ????????????????c????????
????3??Mediahy???????Core Graphics??Core Animation??OpenGL ES??Core Text??Image I/O??Assets Library Framework??Media Player Framework??AV Foundation??OpenAL??Core Audio Frameworks??Core Media???
????4?? Cocoa Touch ??????????Address Book UI Framework??Event Kit UI Framework??Game Kit Framework??iAd Framework??Map Kit Framework??Message UI Framework??UIKit Framework??????????????????? Objective-c????