iOS(iPhone OS or iPhone Operating System)
iOS (formerly iPhone OS or iPhone Operating System) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware. It is the operating system that powers many of the company's mobile devices, including the iPhone; the term also included the versions running on iPads until iPadOS was introduced in 2019, as well as on the iPod Touch devices, which were discontinued in mid-2022. It is the world's second-most widely installed mobile operating system, after Android. It is the basis for three other operating systems made by Apple: iPadOS, tvOS, and watchOS. It is proprietary software, although some parts of it are open source under the Apple Public Source License and other licenses.
iPadOS is a mobile operating system developed by Apple Inc. for its iPad line of tablet computers. It is a rebranded variant of iOS, the operating system used by Apple's iPhones, renamed to reflect the diverging features of the two product lines, particularly the iPad's multitasking capabilities. It was introduced as iPadOS 13 in 2019, reflecting its status as the successor to iOS 12 for the iPad, at the company's 2019 Worldwide Developers Conference. iPadOS was released to the public on September 24, 2019.
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