IPhone OS 1

iOS 1 was the first iOS made. It is the main operating system for First generation iPod touches and First generation iPhones.

Similarities with iOS 5
iPhone OS 1 is very similar with iOS 5 and iOS 4. It lacked many features like Notification Center, Multitasking and Reminders. The user interface was slightly different too, namely the lack of a 3D-like dock, the lack of an app store, and no home screen wallpapers. The OS was definitely faster then today's, but at the time it was 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 Firmware.
 * This Is The First IOS To Feature ITunes.
 * The ITunes Was First Featured On IPhone OS 1.1.1