Study course is to acquaint students in depth with the principles of Windows, Linux, and MacOS operating system (OS) principles, installation, configuration, implementation, possibilities. The study course consists of two parts. The first part looks at the current versions of Microsoft Windows desktop and Windows Server OS. The second part looks at Linux desktops and overviews the latest versions of Linux server operating systems and MacOS. The study course includes both theoretical material about the personal computer OS, their security features, and four practical works on the installation and configuration of various OS.