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iOS is a mobile operating system developed by Apple. Apple first announced this system at the Macworld conference on January 9, 2007. It was originally designed for iPhone, and was later applied to iPod touch and iPad. iOS, like Apple's macOS operating system, is a Unix-like commercial operating system.

Originally, this system was called iPhone OS. Because iPad, iPhone, and iPod touch all use iPhone OS, it was announced at WWDC in 2010 that it was renamed to iOS (iOS is a registered trademark of Cisco Network Equipment Operating System of the United States, Apple The name change has been authorized by Cisco Corporation).