Introduction

iOS is the operating system at the heart of iPhone, iPod touch, and iPad devices.

The iOS platform was built using the knowledge that went into the creation of Mac OS X, and many of the tools and technologies used for development on the platform have their roots in Mac OS X as well. Despite its similarities to Mac OS X, iOS does not require experience developing Mac OS X applications. The iOS Software Development Kit (SDK) provides everything you need to get started creating iOS applications.

Who Should Read This Document
iOS Technology Overview is an introductory guide for anyone who is new to the iOS platform. It provides an overview of the technologies and tools that have an impact on the development process and provides links to relevant documents and other sources of information. You should use this document to do the following:

The iPhone SDK provides the tools and resources needed to create native iPhone applications that appear as icons on the user’s Home screen. Unlike a web application, which runs in Safari, a native application runs directly as a standalone executable on an iPhone OS–based device. Native applications have access to all the features that make the iPhone and iPod touch interesting, such as the accelerometers, location service, and Multi-Touch interface. They can also save data to the local file system and even communicate with other installed applications through custom URL schemes.

In iPhone OS, you develop native applications using the UIKit framework. This framework provides fundamental infrastructure and default behavior that makes it possible to create a functional application in a matter of minutes. Even though the UIKit framework (and other frameworks on the system) provide a significant amount of default behavior, they also provide hooks that you can use to customize and extend that behavior.