The Unix operating system is a powerful and versatile operating system originally developed in the 1960s and 1970s at Bell Labs. It is known for its multitasking capabilities, allowing multiple processes to run simultaneously, and its multi-user functionality, enabling several users to access the system at the same time. Unix is built on a modular design, which means it consists of small, interchangeable components that can be combined to perform complex tasks. This design philosophy has influenced many other operating systems, including Linux and macOS, making Unix a foundational technology in the world of computing.