IPhone OS 1

iPhone OS 1, retroactively referred to as iOS 1, was the first iOS to be publicly released by Apple. It is the main operating system for first generation iPod touches and first-generation iPhones.

Similarities through iOS 5
iPhone OS 1 is very similar to iOS 4 and 5. It lacked many features, such as Notification Center, Multitasking and Reminders. The user interface was different, with the the lack of a 3D-like dock, the lack of an App Store, and no Main Screen wallpapers. The OS was faster and simpler than today's, but at the time it was considered revolutionary.

Trivia

 * This was originally called iPhone OS 1.0
 * Before the name iPhone OS, Apple said the iPhone runs a version of OS X.
 * This Is The First IOS To Feature Its First-ever Firmware.
 * This Is The First IOS To Feature iTunes.
 * The iTunes Was First Featured On iPhone OS 1.1.1