Today, two big competitors lead the smartphone OS market: Google’s Android and Apple’s iOS. While Android is an open-source operating system, iOS is only available on Apple devices.
When the iPhone was First launched in 2007, its operating system was called “iPhone OS”. In 2010, Apple released the iPad, which runs on the same operating system. When the fourth version of the mobile OS was released later that year, Apple chose to rename the operating system “iOS”.