Whether it’s a desktop or laptop computer, a smartphone or a video game system, every modern computer needs an operating system. That’s the core software on the computer that sits between application software and the hardware, distributing memory and computing resources to apps, managing files and enforcing security rules.
Five of the most common operating systems are Microsoft Windows, Apple macOS, Linux, Android and Apple’s iOS.
What Operating Systems Do
Operating systems define how a computer stores files, switches between different applications, manages memory, keeps itself secure, and interacts with peripherals like printers and cameras. Different operating systems take different approaches to all of these, which is why you normally can’t run a Windows program on a Macintosh computer and why permissions look different on an Android phone than on an iPhone.
Some operating systems are designed by groups of people around the world, like the open source, freely available operating system Linux, while others are commercial products made by one company, such as Microsoft’s Windows and Apple’s macOS.
Different operating systems run on different types of hardware and are designed for different types of applications. For example, iOS is designed for iPhones and iPad tablets, while Mac desktops and laptops use macOS. Your computer or smartphone comes equipped with an OS, but you can install another one in some cases.
Microsoft Windows has existed in one form or another since 1985, and it remains the most popular operating system for home and office computers. Its latest versions, including Windows 10, are also used on some tablets, and the OS is used on some web and number-crunching server computers as well. Computers from a wide variety of manufacturers can use Windows.
Initial versions of Windows worked with an earlier Microsoft operating system called MS-DOS, providing a modern graphical interface on top of DOS’s traditional text-based commands. Signature features of Microsoft Windows’s user interface include windows themselves – rectangle-shaped, on-panel screens that represent individual applications. The Windows Start menu has helped generations of users find programs and files on their devices.
Efforts to use versions of the Windows OS for smartphones have been less successful.
Apple’s iOS is one of the most popular smartphone operating systems, second only to Android. It runs on Apple hardware, including iPhones, iPad tablets and iPod Touch media players.
Signature features of iOS include the App Store where users buy apps and download free software, an emphasis on security including strong encryption to limit what unauthorized users can extract from the phone, and a simple, streamlined interface with minimal hardware buttons.
Google’s Android OS
Android is the most popular operating system in the world judging by the number of devices installed. Largely developed by Google, it’s chiefly used on smartphones and tablets. Unlike iOS, it can be used on devices made by a variety of different manufacturers, and those makers can tweak parts of its interface to suit their own needs.
Users can download custom versions of the operating system because large portions of it are open source, meaning anyone can legally modify it and publish their own. However, most people prefer to stick with the version that comes on their devices.
Android, like iOS, comes with an application and media store called the Play Store built by Google. Some phone manufacturers and other organizations also offer their own stores to install software and media.
Apple’s macOS, successor to the popular OS X operating system, runs on Apple laptops and desktops. Based in part on the historic family of Unix operating systems dating back to research in the 1960s at AT&T’s Bell Labs, macOS shares some features with other Unix-related operating systems including Linux. While the graphical interfaces are different, many of the underlying programming interfaces and command line features are the same.
Signature elements of macOS include the dock used to find programs and frequently used files, unique keyboard keys including the Command key, and the stoplight-colored buttons used to resize open program windows. MacOS is known for its user-friendly features, which include Siri, a natural-voice personal assistant, and FaceTime, Apple’s video-calling application.
Linux Operating System
Unlike many other operating systems, development on Linux isn’t led by any one company. The operating system was created by Finnish programmer Linus Torvalds in 1991. Nowadays, programmers from all over the world collaborate on its open source code and submit tweaks to the central kernel software and other programs.
A wide assortment of commercial and open source software is available for Linux, and various Linux distributions provide custom user interfaces and tools for installing software onto machines running the operating system. A favorite of many programmers, Linux is widely used on corporate and scientific servers, including cloud computing environments. Linux can be run on a wide variety of hardware and is available free of charge over the internet.