iOS facts for kids

iOS

iOS 18, the latest release of iOS
Company / developer	Apple
Programmed in	C, C++, Objective-C, Swift, assembly language
OS family	Unix-like, based on Darwin (BSD), macOS
Working state	Current
Source model	Closed, with open-source components
Initial release	June 29, 2007; 18 years ago (2007-06-29)
Latest unstable release	26.0 beta 5  (August 5, 2025; 17 days ago (2025-08-05))
Marketing target	iPhone iPad (until 13.0) iPod Touch (until 16.0)
Available language(s)	Arabic, Bulgarian, Catalan, Chinese Simplified, Chinese Traditional (Hong Kong), Chinese Traditional (Taiwan), Croatian, Czech, Danish, Dutch, English (Australia), English (United Kingdom), English (United States), Finnish, French (Canada), French (France), German, Greek, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Kazakh, Korean, Malay, Norwegian, Polish, Portuguese (Brazil), Portuguese (Portugal), Romanian, Russian, Slovak, Slovenian (iOS 18), Spanish (Latin America), Spanish (Spain), Swedish, Thai, Turkish, Ukrainian, Vietnamese
Update method	Over-the-air (since 5.0) Wired connection
Supported platforms	ARM architecture family ARM64 (since 7.0) ARM32 (until 11.0)
Kernel type	Hybrid (XNU)
Default user interface	Multi-touch GUI
License	Proprietary software except for open-source components

iOS (which used to be called iPhone OS) is a special computer program, or mobile operating system, made by Apple. It runs on their iPhone smartphones. Apple first showed iOS in January 2007 with the very first iPhone. It was released in June 2007.

Apple releases big updates for iOS every year. The newest stable version, iOS 18, became available to everyone on September 16, 2024. Besides iPhones, iOS is the base for other Apple operating systems like iPadOS, tvOS, and watchOS. iOS also used to power iPads until iPadOS came out in 2019. It also ran on iPod Touch devices until they were stopped.

iOS is the second most used mobile operating system in the world, right after Android. As of December 2023, Apple's App Store has over 3.8 million apps for iOS devices. iOS is built on parts of macOS, Apple's computer operating system. It uses parts of the Mach microkernel and FreeBSD. Even though some parts of iOS are open source, most of it is proprietary software, meaning Apple owns it.

The Story of iOS

How iOS Began

In 2005, when Steve Jobs was planning the iPhone, he had a big decision. He could either make a smaller version of the Mac computer's operating system or a bigger version of the iPod's software. Jobs chose to shrink the Mac's system. This led to the creation of iPhone OS.

This choice helped the iPhone become a great platform for apps. Many developers who made software for Macs could easily create apps for the iPhone. A special kit for developers, called a software development kit (SDK), was also made. This kit helped programmers build iPhone apps and led to the App Store.

Launching the iPhone OS

The operating system was first shown with the iPhone on January 9, 2007. It was released in June of that year. At first, Apple didn't let other companies make their own apps for the iPhone. Steve Jobs thought people could use web apps through the Safari web browser instead.

But in October 2007, Apple announced they were working on an SDK. They released it on March 6, 2008. This allowed developers to create native apps.

The App Store's Growth

The iOS App Store opened on July 10, 2008, with 500 apps. It grew very quickly:

• September 2008: 3,000 apps
• November 2009: 100,000 apps
• October 2013: 1 million apps
• June 2016: 2 million apps

By January 2017, there were 2.2 million apps. These apps have been downloaded over 130 billion times.

Expanding to Other Devices

In September 2007, Apple released the iPod Touch. It looked like the iPhone but was an iPod. On January 27, 2010, Apple introduced the iPad. This tablet had a bigger screen than the iPhone and iPod Touch. It was made for browsing the web, watching videos, reading, and using apps.

In June 2010, Apple changed the name from iPhone OS to "iOS." Apple got permission to use the name "IOS" from Cisco, a company that had used it for their router operating system for many years.

The Apple Watch smartwatch was announced in September 2014 and released in April 2015. It uses watchOS, which is also based on iOS. In October 2016, Apple opened its first iOS Developer Academy in Naples, Italy. This academy teaches students how to create apps for Apple devices.

On June 3, 2019, Apple announced iPadOS. This was a special version of iOS made just for the iPad. It launched on September 25, 2019. On June 9, 2025, Apple introduced iOS 26. This new numbering system helps keep all Apple operating systems' versions in sync.

How iOS Works

User Interface

The way you use iOS is based on touching the screen directly. You use multi-touch gestures like swiping, tapping, pinching, and reverse pinching. You also use sliders, switches, and buttons. The device can also respond to shaking or rotating it. For example, shaking can undo something, and rotating can switch between tall (portrait) and wide (landscape) views.

iOS has many accessibility features to help people with vision or hearing difficulties use their devices.

Lock Screen and Home Screen

When you turn on an iOS device, you see the lock screen. It shows the time and widgets, which are small displays of information from apps. After you unlock it, you go to the home screen. This is where you find your apps and information, much like a desktop on a computer.

The home screen has app icons and widgets. App icons open apps, while widgets show live, updating content like the weather or news. At the top of the screen is the status bar, showing things like time, battery, and signal.

Control Center and Notifications

You can pull down from the top right (on iPhones with Face ID) or swipe up from the bottom (on iPhones with Touch ID) to open the Control Center. This lets you quickly change settings like brightness, volume, and Wi-Fi.

Swiping down from the top left (or top to bottom on iPhones with Touch ID) opens the Notification Center. This shows your notifications in order and grouped by app. You can even reply to messages directly from a notification.

Taking Screenshots

On iPhones with Touch ID, you take screenshots by pressing the home and power buttons at the same time. On iPhones with Face ID, you use the volume-up and power buttons.

Context Menus and Selectors

In iOS 13, "context menus" were added. If you touch and hold an item, a menu of related actions appears. When this menu is shown, the background blurs.

To choose from a few options, iOS uses a selection control. These can appear at the bottom of the screen or in line with content. Date selectors, for example, let you pick a day, month, and year.

Alerts

Alerts appear in the middle of the screen. Some alerts, called "action panels," slide up from the bottom. Actions that delete something are usually shown in red.

System Font and Icons

The official font for iOS is San Francisco. It's designed to be easy to read, even for small text. Icons on iPhones with larger screens (over 6 inches) are 180x180 pixels. On smaller screens, they are 120x120 pixels.

Home Screen Features

The home screen, managed by something called SpringBoard, shows your app icons and a dock at the bottom for your most used apps. It appears when you unlock your device, press the Home button, or swipe up from the bottom.

Spotlight Search

In iPhone OS 3, Spotlight was added. This lets you search for apps, emails, contacts, messages, and more. In iOS 7 and later, you can access Spotlight by pulling down anywhere on the home screen. In iOS 9, it also included Siri suggestions for apps and news.

Wallpapers and Parallax

With iPhone OS 3.2, users could set a wallpaper for their home screen. This feature came to iPhones and iPod Touches with iOS 4.

iOS 7 introduced a cool "parallax effect." This makes your wallpaper and icons shift slightly when you move your device. It creates a 3D effect, making icons seem to float.

Folders

iOS 4 brought folders. You can create a folder by dragging one app icon on top of another. You can then add more apps to it. iOS automatically suggests a name for the folder, but you can change it. If apps inside a folder have notifications, the folder itself will show a total number of notifications.

Originally, iPhone folders held up to 12 apps, and iPad folders held 20. With iOS 7, folders were updated to have pages, like the home screen. Each page could hold 9 apps, with up to 15 pages, allowing 135 apps in one folder. In iOS 9, iPad folders could hold 16 apps per page, for a total of 240 apps.

Notification Center

Before iOS 5, notifications appeared in a pop-up window and disappeared after you closed them. In iOS 5, Apple introduced Notification Center. This lets you see a history of your notifications. You can tap a notification to open its app or clear it. Notifications now appear as banners at the top of the screen.

When an app sends a notification while closed, a red badge appears on its icon. This badge shows how many notifications that app has sent. Opening the app clears the badge.

Applications (Apps)

iOS devices come with many preinstalled apps from Apple, like Mail, Maps, Music, and FaceTime.

Apps are the main type of software you can install on iOS. You download them from the official App Store. Apps in the App Store are checked for security before they are available. Apps for iOS are mostly built using UIKit, a special programming framework. This helps apps look and feel consistent with the rest of the operating system.

Apple didn't originally plan to release an SDK for developers. They wanted people to make web apps instead. But because web apps weren't widely used, Apple changed its mind. The SDK for developers was announced in October 2007 and released on March 6, 2008.

The SDK is free for Mac users. It includes tools like an audio mixer and an iPhone simulator. To test apps, get support, and sell apps through the App Store, developers need to join the Apple Developer Program.

The App Store has reached many milestones, including 50,000, 100,000, 250,000, 500,000, 1 million, and 2 million apps. The billionth app was installed on April 24, 2009.

App Library

The App Library automatically sorts your apps into folders based on what they do. For example, all your social media apps might go into one folder. It also has an alphabetical list of all your installed apps. You can quickly find apps using the search bar. You can also hide app pages from your home screen to keep it tidy.

Storage and Files

iOS keeps apps separate from each other for security and privacy. Apps can usually only access their own files. To get to files outside their own space, iOS uses tools like document pickers and file providers.

In iOS 11, Apple introduced the Files app. This app gives you one place to manage and organize your files. Apps can work with the Files app to make their documents available there.

You can also expand your iOS device's storage using iCloud. This is Apple's cloud storage service. It gives all users 5GB of free storage, with more available through paid plans. iCloud Drive lets you store documents, presentations, and other files in the cloud. You can access these files on any of your devices if you're signed in with the same Apple ID.

Accessibility Features

iOS has many features to help users with vision and hearing disabilities. One important feature is VoiceOver. This reads information on the screen aloud, including buttons, icons, and links. It lets users navigate the device using gestures.

Apple also created a "Made for iPhone" program with iOS 7 in 2013. This allows special third-party hearing aids to connect to iPhones and iPads. These devices can stream audio directly to a user's ears.

With iOS 10 in 2016, Apple added more accessibility features. These included a new pronunciation editor for VoiceOver and a Magnifier setting to enlarge objects using the camera. It also added software TTY support for deaf people to make phone calls.

In 2012, Liat Kornowski from The Atlantic said the iPhone was "one of the most revolutionary developments since the invention of Braille". In 2016, Steven Aquino of TechCrunch called Apple a leader in assistive technology.

Multitasking

Multitasking on iOS means running more than one app at a time. It first came out in June 2010 with iOS 4. Only certain devices like the iPhone 4 and iPhone 3GS could multitask at first. The iPad got multitasking later with iOS 4.2.1.

iOS handles multitasking by letting apps do certain tasks in the background. Developers need to add special support for these features.

Switching Between Apps

In iOS 4.0 to iOS 6.x, you double-clicked the home button to open the app switcher. A scrolling bar appeared at the bottom, showing app icons. Tapping an icon switched to that app.

With iOS 7, double-clicking the home button still opened the app switcher. But it showed screenshots of open apps instead of just icons. You could scroll sideways through apps and close them by swiping them up off the screen.

In iOS 9, the app switcher got a new look. It still used the card-like view from iOS 7, but the app icon was smaller and above the screenshot. Apps overlapped, creating a rolodex effect as you scrolled. The home screen appeared at the far right. In iOS 11, the app switcher was redesigned again. On the iPad, the Control Center and app switcher were combined.

Closing Apps

In iOS 4.0 to iOS 6.x, you held down app icons in the switcher until they "jiggled." Then you tapped a red minus circle to close the app.

From iOS 7 onwards, closing apps became faster. You simply swipe the app's screenshot upwards off the screen. You can close up to three apps at once.

Task Completion

Task completion lets apps finish a task even after you switch away from them. Since iOS 4.0, apps can ask for up to ten minutes to complete a task in the background.

Siri

Siri is a virtual assistant built into iOS. You can talk to Siri using your voice to ask questions, get recommendations, and perform actions. Siri learns how you speak and what you prefer over time.

Siri started as a separate app in February 2010. Apple bought it two months later and added it to the iPhone 4S when it was released in October 2011. The separate Siri app was then removed from the App Store.

Siri can do many things, like making phone calls, checking information, setting reminders, changing device settings, searching the internet, and helping with navigation. With iOS 10 in 2016, Apple allowed some third-party apps to work with Siri, like messaging and ride-sharing apps.

In iOS 11, Siri's voice became more natural. It could also answer follow-up questions and translate languages. iOS 17 made it even easier to activate Siri by just saying "Siri," though "Hey Siri" still works.

Game Center

Game Center is an online "social gaming network" from Apple. It lets you invite friends to play games, start multiplayer games, track your achievements, and compare your high scores on leaderboards. iOS 5 and later added support for profile photos.

Game Center was announced in April 2010 and released on September 8, 2010, with iOS 4.1. It came to the iPad with iOS 4.2.1.

Supported Processors

iOS works with ARM processors. Currently, it supports different versions of the ARMv8 and ARMv9 architectures. Before iOS 7 (2013), iOS only supported 32-bit ARM processors. But iOS 7 added full support for 64-bit processors, after Apple introduced the Apple A7 chip.

Since 2015, all new apps and app updates submitted to the App Store must support 64-bit. iOS 11, released in 2017, stopped supporting all 32-bit ARM processors and 32-bit apps, making iOS completely 64-bit.

Devices That Use iOS

iOS runs almost only on Apple's own devices. It powers all iPhones and iPod Touch devices. Apple Watches, Apple TVs, and iPads also use iOS or operating systems based on iOS.

Developing for iOS

The iOS software development kit (SDK) is a set of tools that lets people create mobile apps for iOS devices.

When Apple was first making the iPhone before 2007, Steve Jobs didn't want other developers to make native apps. He wanted them to make web apps for the Safari browser instead. But developers wanted to make full apps, so Apple changed its mind. Jobs announced in October 2007 that an SDK would be available by February 2008. The SDK was released on March 6, 2008.

The SDK is a free download for users of Mac computers. It includes tools that give developers access to different features of iOS devices. It also has an iPhone simulator that lets developers test how their app looks and works on a computer. New versions of the SDK come out with new versions of iOS. To test apps on a real device, get technical help, and sell apps through the App Store, developers need to join the Apple Developer Program.

The iOS SDK, along with a program called Xcode, helps developers write iOS apps using languages like Swift and Objective-C.

How iOS Updates Work

Apple releases big updates for iOS every year. Since iOS 5, the main way to get updates is over-the-air, meaning they download directly to your device. You can also update using iTunes on older computers or Finder on newer Macs.

Your device regularly checks for updates. If enabled, updates download and install automatically. Otherwise, you can install them manually or choose to install them overnight when your device is plugged in and connected to Wi-Fi.

In the past, iPod Touch users had to pay for system updates. But in September 2009, this changed, and iPod Touch updates became free. Apple has also made iOS devices supported for updates for longer periods over the years. For example, the first iPhones only got two iOS updates, while newer models have been supported for five, six, or even seven years.

The XNU Kernel

iOS uses a core part called the XNU kernel. This kernel is also used in macOS and other Apple operating systems like iPadOS, watchOS, and tvOS. It's like the brain of the operating system. Some parts of XNU are open source, meaning their code can be viewed by anyone.

Since iOS 6 (2012), the kernel uses a security technique called kernel address space layout randomization (KASLR). This makes it harder for bad software to find and use weaknesses in the system's memory.

Jailbreaking iOS Devices

Since iOS first came out, people have found ways to modify it. This is called "jailbreaking." Before Apple's App Store, people jailbroke their devices to install apps not approved by Apple. Apple usually fixes the ways people jailbreak with each new iOS update.

When a device is jailbroken, it means its core software (the kernel) has been changed. There are different types of jailbreaks:

• An untethered jailbreak means the device stays jailbroken even after you turn it off and on again.
• A tethered jailbreak means the device is only temporarily jailbroken. If you turn it off, you need to connect it to a computer and use a special tool to jailbreak it again when you turn it back on.
• Semi-tethered and semi-untethered jailbreaks are newer types that offer more flexibility.

People jailbreak for various reasons, such as gaining more control over their device, installing custom themes, or changing how the home screen works. It can also allow the installation of apps not found in the App Store. On some devices, jailbreaking can even allow installing other operating systems like Android.

In 2010, the Electronic Frontier Foundation (EFF) helped make it legal in the U.S. to jailbreak iPhones. This was specifically for installing apps that were legally obtained. However, jailbreaking might still void your iPhone's warranty, meaning Apple might not fix it for free if something goes wrong.

Unlocking iOS Devices

"Unlocking" an iPhone usually means removing the SIM lock. This lock prevents the phone from being used with other wireless carriers. Initially, many carriers in the US didn't allow iPhones to be unlocked. However, AT&T eventually allowed customers who met their contract requirements to unlock their iPhones.

Apple provides instructions for unlocking, but it's up to the carrier to allow it. This lets you use an iPhone bought from one carrier on another network. Modern iOS versions and iPhones support different carriers without needing special unlocking. There are also unofficial ways to remove SIM locks, but these are not supported by Apple.

The legality of software unlocking varies by country. In the US, there was an exemption for unofficial software unlocking of devices bought before January 26, 2013.

Security and Privacy

iOS has many security features built into both its hardware and software. These features help keep your device and your personal information safe.

More to Explore

• Comparison of mobile operating systems

See also

In Spanish: IOS para niños