IPadOS
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 and support for keyboard use. 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. The current public release is iPadOS 15.3.1, released on February 10, 2022.

History 

The first iPad was released in 2010 and ran iPhone OS 3.2, which added support for the larger device to the operating system, previously only used on the iPhone and iPod Touch. This shared operating system was rebranded as "iOS" with the release of iOS 4.

The operating system initially had rough feature parity running on the iPhone, iPod Touch, and iPad, with variations in user interface depending on screen size, and minor differences in the selection of apps included. However, over time, the variant of iOS for the iPad incorporated a growing set of differentiating features, such as picture-in-picture, the ability to display multiple running apps simultaneously (both introduced with iOS 9 in 2015), drag and drop, and a dock that more closely resembled the one in macOS than the one on the iPhone (added in 2017 with iOS 11). Standard iPad apps were increasingly designed to support the optional use of a physical keyboard.

To emphasize the different feature set available on the iPad, and to signal their intention to develop the platforms in divergent directions, at WWDC 2019, Apple announced that the variant of iOS that runs on the iPad would be rebranded as "iPadOS". The new naming strategy began with iPadOS 13.1, in 2019.

On June 22, 2020, at WWDC 2020, Apple announced iPadOS 14, with compact designs for search, Siri, and calls, improved app designs, handwriting recognition, better AR features, enhanced privacy protections, and app widgets. iPadOS 14 was released to the public on September 16, 2020.

On June 7, 2021, at WWDC 2021, iPadOS 15 was announced with widgets on the Home Screen and App Library, the same features that came to the iPhone with iOS 14 in 2020. The update also brought stricter privacy measurements with Safari such as IP Address blocking so other websites cannot see it. iPadOS 15 was released to the public on September 20, 2021.

Features 
Many features of iPadOS are also available on iOS; however, iPadOS contains some features that are not available in iOS and lacks some features that are available in iOS.

iPadOS 13

Home Screen 
Unlike previous versions of iOS, the icon grid displays up to five rows and six columns of apps, regardless of whether the device is in portrait or landscape orientation. The first page of the home screen can be configured to show a column of widgets from applications for easy access. Spotlight Search is no longer part of the widgets but can still be accessed by swiping down from the center of the home screen or pressing Command + Space on a connected keyboard.

Multitasking 

iPadOS features a multitasking system developed with more capabilities compared to iOS, with features like Slide Over and Split View that make it possible to use multiple different applications simultaneously. Double-clicking the Home Button or swiping up from the bottom of the screen and pausing will display all currently active spaces. Each space can feature a single app, or a Split View featuring two apps. The user can also swipe left or right on the Home Indicator to go between spaces at any time, or swipe left/right with four fingers.

While using an app, swiping up slightly from the bottom edge of the screen will summon the Dock, where apps stored within can be dragged to different areas of the current space to be opened in either Split View or Slide Over. Dragging an app to the left or right edge of the screen will create a Split View, which will allow both apps to be used side by side. The size of the two apps in Split View can be adjusted by dragging a pill-shaped icon in the center of the vertical divider and dragging the divider all the way to one side of the screen closes the respective app. If the user drags an app from the dock over the current app, it will create a floating window called Slide Over which can be dragged to either the left or right side of the screen. A Slide Over window can be hidden by swiping it off the right side of the screen, and swiping left from the right edge of the screen will restore it. Slide Over apps can also be cycled between by swiping left or right on the Home Indicator in the Slide Over window and pulling up on it will open an app switcher for Slide Over windows. A pill-shaped icon at the top of apps in Split View or Slide Over allows them to be switched in an out of Split View and Slide Over.

The user can now have several instances of a single app open at once. A new App Exposé mode has been added which allows the user to see all of the instances of an app.

In many applications, a notable exception being YouTube, videos can be shrunk down into a picture-in-picture window so the user can continue watching it while using other apps. This window containing the video can be resized by pinching and spreading and can be docked to any of the four corners of the screen. It can also be hidden by swiping it off the side of the screen and is denoted by an arrow at the edge where the video is hidden and swiping it will bring it back onscreen.

Safari 
Safari now shows desktop versions of websites by default, includes a download manager, and has 30 new keyboard shortcuts if an external keyboard is connected.

Sidecar 
Sidecar allows for an iPad to function as a second monitor for macOS, named in reference to articulated motorcycles. When using Sidecar, the Apple Pencil can be used to emulate a graphics tablet for applications like Photoshop. This feature is only supported on iPads that support the Apple Pencil. However, earlier versions of iPadOS 13 allowed all iPads compatible with iPadOS 13 to work with Sidecar.

Storage 
iPadOS allows external storage, such as USB flash drives, portable hard drives, and solid state drives to be connected to an iPad via the Files app. iPad Pros from the 3rd generation above connects over USB-C, but the Lightning camera connection kit also works to connect external drives with previous iPads.

Mouse and trackpad support 
Mouse and trackpad support was added in version 13.4.

iPadOS 14

Scribble 
Introduced in iPadOS 14, Scribble converts text handwritten by an Apple Pencil into typed text in most text fields.

iPadOS 15

Widgets 
Beginning with iPadOS 15, you can place widgets on the home screen.

Translate 
Beginning with iPadOS 15, Translate is available. The feature was announced on June 7, 2021 at WWDC 2021. Translation works with 11 languages.

References

External links 

  – official site
  – official developer site
 iOS Reference Library at the Apple Developer site

 
IPad
Apple Inc. operating systems
Mach (kernel)
Mobile operating systems
Products introduced in 2019
Tablet operating systems