The Problems of the (Earlier) Plan 9 License
by Richard Stallman
Note: This applies to the earlier license used for Plan 9.
The current license of Plan 9 does qualify as free software (and also
as open source). So this article's specific example is of historical
relevance only. Nonetheless, the general point remains valid.
When I saw the announcement that the Plan 9 software had been released
as “open source”, I wondered whether it might be free
software as well. After studying the license, my conclusion was that
it is not free; the license contains several restrictions that are
totally unacceptable for the Free Software Movement. (See
I am not a supporter of the Open Source Movement, but I was glad when
one of their leaders told me they don't consider the license
acceptable either. When the developers of Plan 9 describe it as
“open source”, they are altering the meaning of that term
and thus spreading confusion. (The term “open source” is
Here is a list of the problems that I found in the Plan 9 license.
Some provisions restrict the Plan 9 software so that it is clearly
nonfree; others are just extremely obnoxious.
First, here are the provisions that make the software nonfree.
You agree to provide the Original Contributor, at its request, with a
copy of the complete Source Code version, Object Code version and
related documentation for Modifications created or contributed to by
You if used for any purpose.
This prohibits modifications for private use, denying the users a
and may, at Your option, include a reasonable charge for the cost
of any media.
This seems to limit the price that may be charged for an initial
distribution, prohibiting selling copies for a profit.
Distribution of Licensed Software to third parties pursuant to this
grant shall be subject to the same terms and conditions as set
forth in this Agreement,
This seems to say that when you redistribute you must insist on a contract
with the recipients, just as Lucent demands when you download it.
1. The licenses and rights granted under this Agreement shall
terminate automatically if (i) You fail to comply with all of the
terms and conditions herein; or (ii) You initiate or participate
in any intellectual property action against Original Contributor
and/or another Contributor.
This seemed reasonable to me at first glance, but later I realized
that it goes too far. A retaliation clause like this would be
legitimate if it were limited to patents, but this one is not. It
would mean that if Lucent or some other contributor violates the
license of your GPL-covered free software package, and you try to
enforce that license, you would lose the right to use the Plan 9 code.
You agree that, if you export or
re-export the Licensed Software or any modifications to it, You are
responsible for compliance with the United States Export
Administration Regulations and hereby indemnify the Original
Contributor and all other Contributors for any liability incurred as a
It is unacceptable for a license to require compliance with US export
control regulations. Laws being what they are, these regulations
apply in certain situations regardless of whether they are mentioned
in a license; however, requiring them as a license condition can
extend their reach to people and activities outside the US
government's jurisdiction, and that is definitely wrong.
A part of the distribution is covered by a further unacceptable
2.2 No right is granted to Licensee to create derivative works of or
to redistribute (other than with the Original Software or a derivative
thereof) the screen imprinter fonts identified in subdirectory
/lib/font/bit/lucida and printer fonts (Lucida Sans Unicode, Lucida
Sans Italic, Lucida Sans Demibold, Lucida Typewriter, Lucida Sans
Typewriter83), identified in subdirectory /sys/lib/postscript/font.
One part of this collection is free—the Ghostscript fonts that
are covered by the GNU GPL. All the rest does not even come
Aside from those fatal flaws, the license has other obnoxious
…As such, if You or any Contributor include Licensed
Software in a commercial offering (“Commercial
Contributor”), such Commercial Contributor agrees to defend
and indemnify Original Contributor and all other Contributors
(collectively “Indemnified Contributors”)
Requiring indemnities from users is quite obnoxious.
Contributors shall have unrestricted, nonexclusive, worldwide,
perpetual, royalty-free rights, to use, reproduce, modify, display,
perform, sublicense and distribute Your Modifications, and to grant
third parties the right to do so, including without limitation as a
part of or with the Licensed Software;
This is a variant of
asymmetry: you get limited rights to use their code, but they get
unlimited rights to use your changes. While this does not by itself
disqualify the license as a free software license (if the other
problems were corrected), it is unfortunate.