IntroductionOperating system is a very important and crucial software system that can help the computer in generating the computer programs, because a computer without an operating system cannot function correctly. So that the operating system can connect to the input device keyboard or mouse, output device like a display or printer and control the disk drive. In the mainframe, the operating system plays a more useful role in helping different types of programs and users run the system. at the same time, without interfering with each other. The operating system is also a security system that protects users from unauthorized access to the system. The operating system consists of different types, from Microsoft, Microsoft Windows 7 is one of the most commonly used types of operating system in computers, the second one is Apple MacOS, this operating system does not exist that in Apple computer and IOS is a system used in Apple phone. Third, Linux OS, a popular variant of computers used by Linux and IBM compatible computers, and Google Android OS, is a system used in Android compatible phones. The operating system can be classified into a few types, one of them being multi-user, which allows 2 or more users to run the program at the same time. The next 1 is multitasking; means a computer can run more than 1 or 2 programs at the same time. Next, there's multithreading, which allows different types of unique programs to run simultaneously and continue in real time by responding instantly to inputs. In this report, we have chosen 3 types of operating system from Windows, Mac and Linux and will explain them in more detail. Windows Operating SystemWindows operating system is established by Microsoft. The graphical user interface is a program middle of paper......the operating system always provides more ported hardware than other operating systems and it runs the operating system on a server like the central computer and supercomputer. After that, multitasking is a crucial feature for Linux, it allows running multiple applications at the same time, which can become more useful in a computer network business to do complex work. Conclusion In the overall study of operating system, we can understand that operating system is crucial and important because it helps every business in the world to carry out their work with computer technology. The technology trend of the last year is rapid growth, which reflects the improvement of the operating system which can be avoided. Operating system users, depending on their demand and required work, will use different types of operating system in order to maximize effectiveness and efficiency to complete their tasks..