IOS



"There's an app for that."

Apple's iOS (formerly "iPhone OS") is the operating system that powers their iPhones, iPods, and iPads. It is derived from OS X, but not compatible (you can use the iOS Simulator to run iOS apps on a Mac). iOS is much more locked down than rival Android, and its app store is much more restrictive (emulators are a huge no-no). You can only run unofficial apps if you "jailbreak" your device. Or save yourself the hassle and just get an Android device instead!