It is available for all i OS devices with 64-bit processors; the i Phone 5S and later i Phone models, the i Pad (2017), the i Pad Air and later i Pad Air models, all i Pad Pro models, the i Pad Mini 2 and later i Pad Mini models, and the sixth-generation i Pod Touch.
In 2005, when Steve Jobs began planning the i Phone, he had a choice to either "shrink the Mac, which would be an epic feat of engineering, or enlarge the i Pod".
This feature is only available on third-generation devices—i Phone 3GS, third-generation i Pod touch (i OS 4.0 or newer), all i Pad models (since i OS 3.2)—or newer.
Researchers found that users organize icons on their homescreens based on usage-frequency and relatedness of the applications, as well as for reasons of usability and aesthetics. Apple switched to Helvetica Neue exclusively for the i Phone 4 and its Retina Display, and retained Helvetica as the system font for older i Phone devices on i OS 4.
In i OS 7 and later, Spotlight is accessed by pulling down anywhere on the home screen (except for the top and bottom edges that open Notification Center and Control Center). As with i OS 7 and 8, pulling down on any homescreen will show Spotlight.
However, it can also be accessed as it was in i OS 3 – 6.
When a passcode is set and a user switches on the device, the passcode must be entered at the Lock Screen before access to the Home screen is granted.
The home screen, rendered by Spring Board, displays application icons and a dock at the bottom where users can pin their most frequently used apps.
The screen has a status bar across the top to display data, such as time, battery level, and signal strength.
The rest of the screen is devoted to the current application.
Jobs favored the former approach but pitted the Macintosh and i Pod teams, led by Scott Forstall and Tony Fadell, respectively, against each other in an internal competition, with Forstall winning by creating the i Phone OS.
The decision enabled the success of the i Phone as a platform for third-party developers: using a well-known desktop operating system as its basis allowed the many third-party Mac developers to write software for the i Phone with minimal retraining.