Jack Kelly reminisces about his time playing Multi-User Dungeons (MUDs) and the transition to becoming a MUD builder. He discusses the challenges of editing MUDs using real languages like C, the frustration of the development cycle, and the clever trick of “copyover” or “hotboot” to update the server without disconnecting users. He delves into the technical details of how copyover works using Unix primitives like pipes, fork(2), and file descriptor persistence across exec(3), highlighting the magic of Unix. Kelly concludes by questioning the modern idioms and seeking further exploration into the intricacies of Unix.
http://jackkelly.name/blog/archives/2025/02/06/how_copyover_mud_servers_worked/