plan 9 from Bell Labs

plan 9 from Bell Labs is a distributed operating system developed at Bell Labs starting in the late 1980s. It was created by the original Unix team, including key figures like Rob Pike, Ken Thompson, and Dennis Ritchie. The system was designed to explore new concepts in distributed computing and graphical user interfaces, moving beyond the limitations of its predecessor. It is named after the cult science fiction film Plan 9 from Outer Space.

History and development

The project originated within the Computing Sciences Research Center at Bell Labs as a successor to Unix, aiming to address its architectural shortcomings in a networked world. Primary architects included Rob Pike, Ken Thompson, Dennis Ritchie, Dave Presotto, and Phil Winterbottom. The first release, dubbed "First Edition," was made available to universities in 1992, with subsequent editions released throughout the 1990s. Development was closely tied to the Bell Labs research environment, with the system used internally for projects like the AT&T network. After Lucent Technologies divested Bell Labs, the Fourth Edition was released under the Lucent Public License in 2002, making it open source. Commercial support was briefly provided by Vita Nuova Holdings.

Design principles and architecture

A foundational principle is that all system resources, including files, devices, and network interfaces, are represented as a hierarchical file system. This unified namespace is accessed via the 9P protocol, a simple protocol for file serving over a network. The system employs a hybrid kernel architecture, but its most notable feature is the seamless integration of distributed resources, allowing processes on different machines to interact as if they were local. The design emphasizes the use of many small, specialized programs communicating via these file interfaces, rather than monolithic applications. Security and authentication are built into the 9P protocol and the namespace construction.

Features and components

The standard graphical interface is provided by rio, a windowing system that itself is a file server. The Acme and Sam text editors, created by Rob Pike, are integral tools that exemplify the system's design philosophy. The rc shell, designed by Tom Duff, serves as the primary command interpreter. Networking is integral, with tools like cpu for starting processes on remote machines and exportfs for serving file systems. The system introduced the UTF-8 character encoding, co-developed by Ken Thompson and Rob Pike, which later became a global standard. Other notable components include the plumber for inter-application messaging and the /proc file system for process management.

Reception and influence

While never achieving widespread commercial adoption like Unix or Linux, plan 9 was highly influential in academic and research circles. It won the ACM Software System Award in 1995 for its innovative design. Its concepts, particularly the universal file system model and the 9P protocol, have inspired numerous other projects. The design of the Inferno operating system, also from Bell Labs, directly inherited its principles. The Go (programming language), created by Robert Griesemer, Rob Pike, and Ken Thompson, was developed in part due to experiences with software development on plan 9. Its ideas on distributed systems presaged many concepts in modern cloud computing.

Derivatives and successors

Several operating systems and environments have been derived from or inspired by its code and concepts. The most direct descendant is 9front, a fork that continues active development with an emphasis on security and new hardware support. Other community forks include 9legacy and Plan 9 from User Space (plan9port), which ports the user environment to run on other systems like Linux, macOS, and Windows. The Inferno OS, created by members of the original team, uses a virtual machine and shares the core design philosophy. Research projects at institutions like the MIT and University of California, Berkeley have also built upon its architectural ideas.

Category:Bell Labs Category:Distributed operating systems Category:Research Unix Category:Plan 9 from Bell Labs