Plan 9 from Bell Labs

Plan 9 from Bell Labs is an operating system, developed in the late 1980s by Bell Laboratories that had previously been developed Unix. It is named after the movie Plan 9 from Outer Space (1959 ) Ed Wood, in which the aliens dead back to life ( it can be found in Plan 9 other allusions to the work of Ed Wood, such as the mascot Glenda is due to the film Glen or Glenda (1953 ) ).

Plan 9 is used as a platform for research projects in the areas of ( UNIX) operating systems and networks.

2011 split a group of Plan 9 developers - from dissatisfaction with the development - under the motto "The front fell off" a fork of the system under the name Plan 9 from front.

Features and Design

A complete installable system currently exists only for the x86 processors and the Raspberry Pi, but overall Intel, MIPS, DEC Alpha, PowerPC, Sparc, Sparc64 and ARM architectures are supported, ie plan 9 runs on the iPAQ Pocket PC ( here called Bitsy ). In addition, a port exists on the virtual machine Xen. The system is written in a dialect of ISO -C and supports UTF -8 ( Unicode). For optimal use a three - button mouse is required. Plan 9 contains, inter alia, the window system rio ( 1), the editor sam (1 ), a type Fenster-/Dateimanager named acme ( 1) and the command line interpreter rc ( 1). A number of software packages, such as Perl, Python and TeX have been ported and are sold separately.

The developers want " What Unix really trying to achieve? " With Chart 9 an answer to the question. In one sentence answer is this:

The concept of file has been extended such that all resources (files, screens, user, computer, etc.) have a name and how files are accessed. There is a standard protocol called 9P, to address these resources. Also, all file system hierarchies are combined into a single large hierarchy. Concrete examples of the impact of these principles: Achievable servers are part of the file system, running programs are part of the file system, etc.

This underlying concept is extremely obvious and easy to see through. However, it has hardly found its way into the popular operating systems because some radical modifications to the software architecture are required. An exception is the inclusion of the / proc file system in Linux and other operating systems, which all programs a uniform and usually backward-compatible way to access data, such as the number of running processes, system load, number of network connections allowed etc. - all about the conventional file system interface. The " everything is a file " idea is further supported under Linux in the virtual file system sysfs and configfs.


On the development of Plan 9 a number of well-known people have been involved, including Ken Thompson, who was temporarily head of the project and was involved in the first versions of Unix, as well as the development of the C programming language.

  • The internal development began in 1987
  • The productive use at Bell Labs took place from 1989 onwards.
  • Plan 9 from Bell Labs First Edition was published in 1993 and has been reported exclusively at universities.
  • Plan 9 from Bell Labs Second Edition was published in 1995 and could be purchased for $ 350.
  • Plan 9 from Bell Labs Third Edition (Brazil ) was published on June 7, 2000 under the specially created Plan 9 license.
  • Plan 9 from Bell Labs Fourth Edition was published in April 2002 and led to fundamental changes. Among other things, 9P has been completely revised ( eg introduction of long file names ), fossil (4 ) ( a new file system ) and venti (8) ( a backup server) added to the system and significantly improves the installation routine. Starting with this release schedule is 9 according to OSI open source and free software as defined by the Free Software Foundation.

In February 2014 was Plan 9, hitherto standing under the Lucent Public License, re-licensed under the GPL.