The primary functions of an operating system (OS) include managing hardware and software resources, providing a user interface, and ensuring system security.

An operating system is an essential component of a computer system, acting as an intermediary between the user and the computer’s hardware. It is tasked with coordinating activities and sharing resources among hardware components. This involves managing the computer’s memory, processing power, and storage. The OS determines which processes have access to specific resources and when they can use them, ensuring that operations are executed both efficiently and fairly.

Additionally, the OS provides a user interface, a vital feature that allows users to interact with the computer system. This interface can be graphical, as seen in Windows or macOS, where users engage with visual elements on the screen, or command-line based, like in UNIX, where users input commands via text. The user interface enhances accessibility, enabling users to perform tasks, run applications, and manage files effectively.

Another crucial function of an operating system is managing system security. The OS safeguards against unauthorized access by requiring user authentication, typically through a password, before granting access. Furthermore, it regulates user permissions, determining which resources and operations each user can access. This function is especially important in multi-user environments, where different users may have varying levels of access rights.

Moreover, the operating system manages system tasks, including controlling peripheral devices like printers and scanners, maintaining the file system, and handling errors. It also provides a platform for software applications to operate. When a user launches an application, the OS allocates the necessary resources and ensures the application runs smoothly.

In conclusion, the operating system serves as the backbone of a computer system, managing both hardware and software resources, facilitating user interaction through a user interface, and ensuring robust system security. It acts as a bridge between the user and the computer, enabling users to engage with their systems and run applications effectively.