The iPod Touch uses iOS as it's main platform although attempts to install Android OS are succesful only in a jailbroken iPod Touch first gen without audio. iOS, the operating system that runs on the iPod Touch, has generally received a major update each year in June. iOS was formerly called iPhone OS, until the release of version 4.0. The first major update after the initial release was iPhone OS 2.0. This update introduced the App Store, which allowed third-party applications for the first time. iPhone OS 2.0 debuted June 29, 2008. iPhone users received the update for free, while iPod Touch users had to pay for the update. The second major update to the operating system, iPhone OS 3.0, was released June 17, 2009. iPhone OS 3.0 added features such as cut, copy, and paste; data tethering; and push notification support. As with the previous major release, iPhone users received the update for free, while iPod Touch users had to pay for the update. iOS 4.0 was made available to the public on June 21, 2010. It was the first major iOS release to drop support for some devices; the first generation iPod Touch and original iPhone are not supported in iOS 4.0. The iPhone 3G and second generation iPod Touch had limited functionality under iOS 4.0, while the iPhone 4, iPhone 3GS, third generation iPod Touch, and fourth generation iPod Touch had full functionality under iOS 4.0. The major features introduced in iOS 4.0 included iBooks, FaceTime, and multitasking. iOS 5.0 was previewed to the public on June 6, 2011, and is expected to be released in the fall of 2011. Apple has received criticism for charging iPod Touch owners for major iOS updates that iPhone owners receive for free, as well as excluding certain features from the iPod Touch software that are included in the iPhone.Apple has said that they can add features for free to the iPhone because the revenue from it is accounted for on a subscription basis under accounting rules, rather than as a one time payment.At WWDC in June 2010, Jobs announced that Apple had "found a way" to make subsequent OS upgrades available free to iPod Touch owners. However, iOS 4.0 and onwards isn't available for the first generation iPod Touch, and some features are only available for the 32GB and 64GB third generation iPod Touch released in September 2009 and the fourth generation iPod Touch released in 2010. In June 2011, iOS 5, the fifth major release of iOS software, was announced at Apple's WWDC 2011. iOS 5 is expected to be publicly released sometime during the Fall of 2011, and will be available on the iPhone 3GS, iPhone 4 (GSM & CDMA versions), iPod touch (3rd & 4th generations), iPad, and iPad 2. Some of its new features include Notification Center, iMessage, Newsstand, Reminders, and Twitter integration. In addition, iOS 5 will come bundled with iCloud.
Comparison to the iPhoneEdit
The iPod touch and the iPhone share essentially the same hardware and run the same iOS operating system. The iPod touch lacks some of the iPhone's features and associated apps, such as access to cellular networks, GPS navigation (and speaker on older models). Although the SMS and Phone apps are included on the iPod touch software, they are disabled and therefore not visible. Also, the sleep/wake button was on the opposite side, up until the release of the iPod touch 4th generation. As a result, the iPod touch is slimmer and lighter than the iPhone. Steve Jobs once referred to the iPod touch as "training wheels for the iPhone".