FreeDOS

FreeDOS is an open-source operating system that allows computers to function similar to older MS-DOS systems. It's designed for running legacy software, managing hardware, or learning about computer fundamentals without needing modern operating systems. FreeDOS is freely available, customizable, and compatible with many DOS-based programs and games, making it useful for hobbyists, developers, or those working on specialized legacy systems. It operates via command-line interactions and can run on older or newer hardware, providing a flexible environment for tasks that don’t require modern graphical interfaces.