An operating system is the most essential program that allows a computer to run and execute programs. Without an operating system, a computer cannot be of any important use since the computer's hardware won't be able to communicate with the software.
An operating system plays an important role of managing software, processes, memory and hardware. It allows a user to execute programs and communicate with the computer. It also allows communication between the hardware and the software thus making it easy for tasks to be completed. It tells the computer what to do by controlling the system components, such as the processor and disk space. The three most common types of operating systems include Microsoft Windows, Linux and Mac OS X.