What is IOS:

iOS (previously iPhone OS) is a mobile operating system developed and distributed by Apple Inc. Originally released in 2007 for the iPhone andiPod Touch, it has been extended to support other Apple devices such as the iPad and Apple TV. Unlike Microsoft's Windows CE (Windows Phone) and Google's Android, Apple does not license iOS for installation on non-Apple hardware .
iOS is derived from OS X, and is therefore a Unix operating system. iOS is Apple's mobile version of the OS X operating system used on Apple computers.

In iOS, there are four abstraction layers: the Core OS layer, the Core Services layer, the Media layer, and the Cocoa Touch layer(is a UI framework for building software programs to run on the iPhone, iPod Touch, and iPad from Apple Inc.) The current version of the operating system (iOS 6.0) dedicates 1-1.5 GB of the device's flash memory for the system partition

Elegant and intuitive interface

You know how to use iPhone, iPad, and iPod touch from the first time you pick them up. That’s because the revolutionary Multi-Touch interface in iOS was designed for your finger. And the simple, beautiful Home screen is the easiest place to start. From built-in apps to over 700,000 more apps and games available on

the App Store. Everything you touch is easy, intuitive, and fun.

Amazing features :

1.Siri :

Siri lets you use your voice to send messages, schedule meetings, place phone calls, and more.Ask Siri to do things just by talking the way you talk. Siri is so easy to use and does so much, you’ll keep finding more and more ways to use it.

2- Maps :
Designed by Apple from the ground up, Maps gives you turn-by-turn spoken directions, interactive 3D views, and the stunning Flyover feature.¹ All in a beautiful vector-based interface that scales and zooms with ease.

3- Music :

Listen to music everywhere. See it, too: You can browse your collection by album art. And since iTunes in the iCloud lets you access the music you purchase on every device you use, you’ll never find yourself without a song. It’s all part of iCloud and iTunes.

4. Face Time :

you can make video calls over Wi-Fi from your iOS device to someone else’s. You can even make FaceTime calls over cellular networks on your iPhone or iPad. And be there in person, even when you’re not

5-Messages

Messages includes iMessage, a messaging service that’s even better than texting because it’s free over Wi-Fi for you and anyone using an iOS device or Mac. And it’s unlimited.⁵ So text all you want, and send photos, videos, locations, and contacts, too. Or ask Siri to do it for you.

6-Safari

It’s the world’s most popular mobile browser. And it gets even better with iOS 6. Not only can you remove clutter from web pages with Reader, now you can save your Reading List for offline perusing. iCloud Tabs keeps track of which pages you have open on your devices, so you can start browsing on one device and pick up where you left off on another device.

7-AirPlay

AirPlay lets you wirelessly stream what’s on your iOS device to your HDTV and speakers via Apple TV. Or mirror exactly what’s on your display to the big screen.⁶ Vacation photos, blockbusters, the latest games — you choose how to go big.

8-Game Center

Game Center lets you expand your social gaming network, turning friends into opponents and opponents into friends. Or go up against people you don’t know in a multiplayer game. It’s your world. Everyone else is just playing in it.