http://plan9.bell-labs.com/plan9/

PlanNine is one of several OperatingSystems from BellLabs. Unix is one, see: QuarterCenturyOfUnix. KenThompson, one of BellLabs inventors, once said "Unix wasn't fun anymore" and "Why is X so big?" when describing why they wrote Plan9.

In Plan9, almost everything is a file server. Your windowing system provides a file service so that for any current window, you can use the filename: /mnt/wsys/text to see what's in it. That means the window itself has the history that you can grep, it doesn't need to be built into this shell, that application, et cetera. That's an example of OnceAndOnlyOnce.

The Plumber is an example of refactoring. Having seen that many tools use a sort of "Pattern match? do Action" model, e.g. awk, sed, perl, make, ..., they created plumbing. The Plumber serves a file system too. Write stuff like mail messages, urls, web pages, etc to /mnt/plumber/send and the plumber process does the matching and launches an appropriate action. Plumbing is new with release 3 of Plan9 and the latest releases of Inferno.

Sounds like the Plumber is a Pattern IDE built into the user environment.

The design and coding philosophy of Plan9 may create the following paradox: The memory footprint and the lines of code for Plan9 may actually get smaller as it grows in usability and functionality. -- ChrisGarrod

Now OpenSource... The '''ENTIRE DISTRIBUTION''' is only 65Mbytes!
http://plan9.bell-labs.com/plan9dist/
This is a really exciting development. 65Mbytes? You probably have more RAM than that.

See http://www.gnu.org/licenses/license-list.html

The Plan 9 License as of June 2003

	 :	This is a free software license, incompatible with the GNU GPL. We recommend that you not use this license for new software that you write, but it is ok to use and improve Plan 9 under this license.

20140216 now under GPLv2 http://tech.slashdot.org/story/14/02/16/0319238/plan-9-from-bell-labs-operating-system-now-available-under-gplv2

See:
	* http://plan9.bell-labs.com/plan9/
	* http://ninetimes.cat-v.org/ -- News abut Plan 9, Inferno and related projects.
	* http://doc.cat-v.org/plan_9/ -- A documentation archive of papers and other information.
	* http://man.cat-v.org -- Man pages.
	* news:comp.os.plan9
	* http://cm.bell-labs.com/wiki/plan9/plan_9_wiki/ -- A Wiki!
	* WhatIsNotInPlanNine -- things were left out because they were hacks to begin with.
	* WhatIsInPlanNine -- novel ideas, broadly applied, lead to this OS
	* PlanNineFromUserSpace -- A port of Plan 9 user space to Unix systems.
	* http://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs

Where did they get the name?

''Obviously it's a play on the title of the movie mentioned below, and there's at least a little theme there with names related to movies: the Plan 9 window system is called 8½, and the current version of Plan 9 was called "Brazil" for a while.'' -- '''And its mascot-bunny is called Glenda. "How can you tell?"'''

http://upload.wikimedia.org/wikipedia/en/7/7e/Plan9bunnysmblack.jpg

http://glenda.cat-v.org

'''(Its fur looks a bit too trim for it to be an angora, which is presumably why it's not called Ed.)'''

These programmers like to start over from scratch. They have been seen to post "Write two, you'll throw one away." They have a new windowing system named '''rio''' which is crisp and slick. It's included on the installer floppy, along with dozens of other tools to accomplish the installation, such as awk, gzip, TCP/IP, etc -- '''All on a 1.44MB floppy!''' -- just playing in that environment is pretty amazing.

* If you think this is amazing take a look at OberonLanguage and OberonOperatingSystem - the complete OS with a compiler, WM, editor, networking fits on one floppy (+ some bonus packages on other disks)

''There is also the MenuetosOperatingSystem, a single floppy OS with a GUI HTML4 browser, editor, C compiler. And then there is QnxOs. Version 4 had a single floppy edition at http://demodisk.qnx.com/ (BrokenLink), again with a GUI HTML4 browser and a webserver(!).''

''Another answer to the question comes from RobPike, who said that the name was chosen "in the Bell Labs tradition of choosing names that make marketeers wince." -- GlennVanderburg''

Don'tSee:
	* the movie named PlanNineFromOuterSpace.

With Release 4 in 2002, they have a completely redone their security model. See http://doc.cat-v.org/plan_9/4th_edition/papers/auth, and then they moved their sources server outside their firewall. (PoweredByPlanNine of course)
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See PlanNineFromUserSpace for ports of some of the PlanNine code to other operating systems.
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CategoryOperatingSystem