Compatible Time-Sharing System (CTSS) Operational

CTSS was one of the first successful time-sharing operating systems, allowing multiple users to log in and interact with a single mainframe simultaneously via Teletype terminals. This marked a profound shift from batch processing to interactive computing.

Significance

CTSS directly introduced the concept of a multi-user, interactive command-line environment, where users typed commands and received immediate feedback, laying the foundation for all subsequent CLIs.