Operating System
WHAT IS AN OPERATING SYSTEM
the low-level software that supports a computer's basic functions, such as scheduling tasks and controlling peripherals.
MAIN FUNCTIONS
TYPES OF OPERATING SYSTEMS and examples
Windows, Linux, and Android are examples of operating systems that enable the user to use programs like MS Office, Notepad, and games on the computer or mobile phone. It is necessary to have at least one operating system installed in the computer to run basic programs like browsers.

USER INTERFACE EXAMPLES
Some popular, modern graphical user interface examples include Microsoft Windows, macOS, Ubuntu Unity, and GNOME Shell for desktop environments, and Android, Apple's iOS, BlackBerry OS, Windows 10 Mobile, Palm OS-WebOS, and Firefox OS for smartphones.
SECURITY AND OPERATING SYSTEMS
Operating system security (OS security) is the process of ensuring OS integrity, confidentiality and availability. OS security refers to specified steps or measures used to protect the OS from threats, viruses, worms, malware or remote hacker intrusions.
HISTORY OF OPERATING SYSTEMS
The first operating system used for real work was GM-NAA I/O, produced in 1956 by General Motors' Research division for its IBM 704.