Operating System (OS) is one of the core software programs that runs on the hardware and makes it usable for the user to interact with the hardware so that they can send commands (input) and receive results (output). It provides a consistent environment for other software to execute commands. So we can say that the OS acts at the center through which the system hardware, other software, and the user communicate. The following figure shows the basic working of the operating system and how it utilizes different hardware or resources.

An operating system has three main functions: (1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers, (2) establish a user interface, and (3) execute and provide services for applications software. Keep in mind, however, that much of the work of an operating system is hidden from the user; many necessary tasks are performed behind the scenes. In particular, the first listed function, managing the computer's resources, is taken care of without the user being aware of the details. Furthermore, all input and output operations, although invoked by an applications program, are actually carried out by the operating system. Although much of the operating system functions are hidden from view, you will know when you are using an applications software package, and this requires that you invoke-call into action-the operating system. Thus you both establish a user interface and execute software.

Five more useful functions that describes the above three main function.

1. Interface between the user and the hardware: An OS provides an interface between user and machine. This interface can be a graphical user interface (GUI) in which users click onscreen elements to interact with the OS or a command-line interface (CLI) in which users type commands at the command-line interface (CLI) to tell the OS to do things.

2. Coordinate hardware components: An OS enables coordination of hardware components. Each hardware device speaks a different language, but the operating system can talk to them through the specific translation software called device drivers. Every hardware component has different drivers for Operating systems. These drivers make the communication successful between the other software and the hardware.

 

3. Provide environment for software to function: An OS provides an environment for software applications to function. An application software is a specific software which is used to perform specific task. In GUI operating systems such as Windows and mac-OS, applications run within a consistent, graphical desktop environment.


4. Provide structure for data management: An OS displays structure/directories for data management. We can view file and folder listings and manipulate on those files and folders like (move, copy, rename, delete, and many others).


5. Monitor system health and functionality: OS monitors the health of our system’s hardware, giving us an idea of how well (or not) it’s performing. We can see how busy our CPU is, or how quickly our hard drives retrieve data, or how much data our network card is sending etc. and it also monitors system activity for malware.