Plan 9 - Computer Definition
A distributed operating system developed at Bell Labs that is known for its simplicity and low overhead. Although Plan 9 came from the same organization that created Unix, and it uses similar commands, Plan 9 is not Unix. All resources in a Plan 9 system are structured as files and accessed via the 9P protocol. The last release of Plan 9 was the fourth edition in 2002, which upgraded 9P to 9P2000. See Inferno and distributed operating system.