• In addition to hardware, a computer requires software to function. The software sends instructions to the hardware to perform the required tasks.  
• The most important computer software is the operating system which controls and manages the hardware connected to your computer. The operating system provides an interface that helps you to use the computer.  
• User interface can be either text-based or graphic based. Most operating systems provide a graphical user interface (GUI) that displays images and graphics to make the computer easier to use.  
• Operating system with GUI provides an easy-to-use interface to help you install hardware or software, for example, window vista provides a setup wizard that walks the user through each step of a particular task, such as installing hardware or software guides.  
• The operating system makes sure that your computer is working properly. You will need to update your operating system regularly to make sure that your computer is compatible with any new hardware that you install.

 Popular operating systems:

• For Windows: Windows 10, Windows 11.
• For macOS: Big Sur, Catalina, etc.

 How does an operating system work: An OS is the program that, after being initially loaded into the computer by a boot program, manages all of the other application programs in a computer.