The Operating System is a base infrastructure software component of a computerized system. It controls all basic operations of the computer (or other electronic devices such as PDA, smartphone, etc.). The Operating System allows the user to install and execute third-party applications (commonly called apps for short), usually adding new functionality to the device.
For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computer – from cellular phones and video game consoles to web servers and supercomputers.
The dominant desktop operating system is Microsoft Windows with a market share of around 82.74%. macOS by Apple Inc. is in second place (13.23%), and the varieties of Linux are collectively in third place (1.57%).
In the mobile sector (including smartphones and tablets), Android's share is up to 70% in the year 2017. According to third quarter 2016 data, Android's share on smartphones is dominant with 87.5 percent with also a growth rate of 10.3 percent per year, followed by Apple's iOS with 12.1 percent with per year decrease in market share of 5.2 percent, while other operating systems amount to just 0.3 percent. Linux distributions are dominant in the server and supercomputing sectors. Other specialized classes of operating systems, such as embedded and real-time systems, exist for many applications.
Mobile devices with a proper OS are called smartphones and users have a wide choice of applications, such as games, productivity apps, communication or social media apps, digital maps, etc.
While the major players these days are clear, over the years we've seen the emergence of numerous mobile OS projects including but not limited to Palm's webOS, Samsung's Bada OS, Nokia's Maemo OS, Nokia's MeeGo OS, LiMo OS, Tizen, BlackBerry's Playbook OS and more recently, the Jolla's Sailfish OS and Mozilla's Firefox OS.