About the iOS Technologies

iOS is a mobile operating system developed and distributed by Apple Inc. that runs on iPad, iPhone, and iPod touch devices. The operating system manages the device hardware and provides the technologies required to implement native apps. The operating system also ships with various system apps, such as Phone, Mail, and Safari that provide standard system services to the user.The iOS Software Development Kit (SDK) contains the tools and interfaces needed to develop, install, run, and test native apps that appear on an iOS device’s Home screen. 

The iOS Software Development Kit (SDK) contains the tools and interfaces needed to develop, install, run, and test native apps that appear on an iOS device’s Home screen. Native apps are built using the iOS system frameworks and Objective-C language and run directly on iOS. Unlike web apps, native apps are installed physically on a device and are therefore always available to the user, even when the device is in Airplane mode.

The iOS SDK provides the resources you need to develop native iOS apps. 

The iOS Technologies Are Packaged as Frameworks

·    Apple delivers most of its system interfaces in special packages called

frameworks.

·    A framework is a directory that contains a dynamic shared library and the

resources (such as header files, images, and helper apps) needed to support that

library.

·   To use frameworks, you add them to your app project from Xcode.

The Developer Library Is There to Help You

·   The iOS Developer Library is an important resource for you to use during development.

·    The library contains API reference, programming guides, release notes, tech notes, sample code, and many other resources offering tips and guidance about the best way to create your apps.

·   You can access the iOS Developer Library from the Apple Developer website or from Xcode. In Xcode, choose Help > Documentation and API Reference to display the Xcode documentation window, which is the central resource for accessing information about iOS development. Use the documentation window to browse, search, and bookmark documents. 

The iOS Architecture Is Layered:

·   iOS acts as an intermediary between the underlying hardware and the apps you create.

·     Apps do not talk to the underlying hardware directly. Instead, they communicate with the hardware through a set of well-defined system interfaces. These interfaces make it easy to write apps that work consistently on devices having different hardware capabilities.

 The implementation of iOS technologies can be viewed as a set of layers:

1.       Lower layers contain fundamental services and technologies.

2.       Higher-level layers build upon the lower layers and provide more sophisticated services and technologies.

Next, we will  learn about the Layers of iOS:  iOS Technology Overview - Layers of iOS