The operating system represents programs that perform computer operations and without which the computer system would not be able to function. In addition, it allows performance of specific tasks requested by users, run all parts of the computer, and supervises their work. Some of the main roles of the operating system are: facilitating the use of computers, efficient use of all parts of the computer, enabling multi-program operation and interaction between multiple computers connected in a network, and managing computing resources that are important to solve individual problems effectively. Most operating systems have several basic concepts on which they are built, and this paper briefly explains processes, address spaces, files, input/output, and security. The purpose of this paper is to analyze the architecture of modern operating systems, so the main types of architectures are described. The operating system must be carefully designed to work properly, and is divided into components that should be a welldefined part of the system and that make up the operating system architecture. This paper gives an example of the architecture of the Microsoft Windows operating system. This operating system separates applications from the operating system itself. The operating system kernel code runs in kernel mode and has access to hardware and system data, while the application code runs in user mode and has a limited set of available interfaces, limited access to system data, and no direct access to hardware. There are numerous advantages, and thus disadvantages of operating systems, and in order to reduce the disadvantages it is necessary to build better, safer and more reliable operating systems that will make a shift compared to current operating systems.