Devices that run with iOS

This is a list and comparison of devices designed and marketed by Apple Inc. (formerly. Apple Computer Inc.) that run a Unix-like operating system named iOS, often referred to simply as iDevices. The devices include the iPhone multimedia smartphone, the iPod Touch, which is similar to the iPhone but has no cell phone hardware, and the iPad tablet computer. All three devices function as digital audio and portable media players and Internet clients. The Apple TV, which ran iOS from the second generation of hardware onwards, is a set-top box for streaming local media to a connected television set, and has no screen of its own.
The operating system on iOS devices can be updated through iTunes, or, on iOS 5 or later, using firmware-over-the-air (FOTA). A major version of iOS tends to be released every time a new type of iPhone is launched, (about once a year) and is normally free, although iPod Touch users were formerly required to pay for the update. Apple upgrades its products' hardware periodically (approximately yearly). There have been six generations of iPhone (original iPhone, iPhone 3G, iPhone 3GS, iPhone 4, iPhone 4S and iPhone 5), five of iPod Touch (1st to 5th generations), and four of iPad (iPad (1st generation), iPad 2, iPad (3rd generation) and iPad (4th generation)).