Before Windows, MacOS and Linux, there was UNIX... How did this groundbreaking operating system revolutionize computing? This seminal paper introduces UNIX, a general-purpose, multi-user, interactive operating system designed for Digital Equipment Corporation PDP-11 computers. It highlights key features often absent in even larger systems, including a hierarchical file system with demountable volumes, compatible file, device, and inter-process I/O, and asynchronous process initiation. The article also emphasizes the system's adaptability, allowing per-user selection of the command language, and its versatility, incorporating over 100 subsystems, including a variety of programming languages. The authors delve into the implementation of the file system, detailing its structure and functionality. They also explain the user command interface, providing insight into how users interact with the system. This foundational work offers a unique glimpse into the design and implementation of an operating system that shaped the landscape of modern computing. It serves as a valuable historical document for understanding the evolution of operating systems and their impact on software development.
This paper, published in Communications of the ACM, aligns perfectly with the journal's focus on computer science and technology. The introduction of the UNIX time-sharing system was a pivotal moment in the field, fitting the journal's focus. The citations to and from ACM publications indicate the paper's integration within computer science literature. Its continued relevance validates its significance.