Topic summary
Plan 9 from Bell Labs
Plan 9 from Bell Labs is an operating system designed by the Computing Science Research Center (CSRC) at Bell Labs in the mid-1980s, built on the UNIX concepts first developed there in the late 1960s. Since 2000, Plan 9 has been free and open-source. The final official release was in early 2021.
Under Plan 9, UNIX's everything is a file metaphor is extended via a pervasive network-centric (distributed) filesystem, and the cursor-addressed, terminal-based I/O at the heart of UNIX is replaced by a windowing system and graphical user interface without cursor addressing (although rc, the Plan 9 shell, is text-based). Plan 9 also introduced capability-based security and a log-structured file system called Fossil that provides snapshotting and versioned file histories.
The name Plan 9 from Bell Labs is a reference to the Ed Wood 1957 cultscience fictionZ-moviePlan 9 from Outer Space. The system continues to be used and developed by operating system researchers and hobbyists.