\section{History of the software} Python was created in the early 1990s by Guido van Rossum at Stichting Mathematisch Centrum (CWI, see \url{http://www.cwi.nl/}) in the Netherlands as a successor of a language called ABC. Guido remains Python's principal author, although it includes many contributions from others. In 1995, Guido continued his work on Python at the Corporation for National Research Initiatives (CNRI, see \url{http://www.cnri.reston.va.us/}) in Reston, Virginia where he released several versions of the software. In May 2000, Guido and the Python core development team moved to BeOpen.com to form the BeOpen PythonLabs team. In October of the same year, the PythonLabs team moved to Digital Creations (now Zope Corporation; see \url{http://www.zope.com/}). In 2001, the Python Software Foundation (PSF, see \url{http://www.python.org/psf/}) was formed, a non-profit organization created specifically to own Python-related Intellectual Property. Zope Corporation is a sponsoring member of the PSF. All Python releases are Open Source (see \url{http://www.opensource.org/} for the Open Source Definition). Historically, most, but not all, Python releases have also been GPL-compatible; the table below summarizes the various releases. \begin{tablev}{c|c|c|c|c}{textrm}% {Release}{Derived from}{Year}{Owner}{GPL compatible?} \linev{0.9.0 thru 1.2}{n/a}{1991-1995}{CWI}{yes} \linev{1.3 thru 1.5.2}{1.2}{1995-1999}{CNRI}{yes} \linev{1.6}{1.5.2}{2000}{CNRI}{no} \linev{2.0}{1.6}{2000}{BeOpen.com}{no} \linev{1.6.1}{1.6}{2001}{CNRI}{no} \linev{2.1}{2.0+1.6.1}{2001}{PSF}{no} \linev{2.0.1}{2.0+1.6.1}{2001}{PSF}{yes} \linev{2.1.1}{2.1+2.0.1}{2001}{PSF}{yes} \linev{2.2}{2.1.1}{2001}{PSF}{yes} \linev{2.1.2}{2.1.1}{2002}{PSF}{yes} \linev{2.1.3}{2.1.2}{2002}{PSF}{yes} \linev{2.2.1}{2.2}{2002}{PSF}{yes} \linev{2.2.2}{2.2.1}{2002}{PSF}{yes} \linev{2.2.3}{2.2.2}{2002-2003}{PSF}{yes} \linev{2.3}{2.2.2}{2002-2003}{PSF}{yes} \linev{2.3.1}{2.3}{2002-2003}{PSF}{yes} \linev{2.3.2}{2.3.1}{2003}{PSF}{yes} \end{tablev} \note{GPL-compatible doesn't mean that we're distributing Python under the GPL. All Python licenses, unlike the GPL, let you distribute a modified version without making your changes open source. The GPL-compatible licenses make it possible to combine Python with other software that is released under the GPL; the others don't.} Thanks to the many outside volunteers who have worked under Guido's direction to make these releases possible. \section{Terms and conditions for accessing or otherwise using Python} \centerline{\strong{PSF LICENSE AGREEMENT FOR PYTHON \version}} \begin{enumerate} \item This LICENSE AGREEMENT is between the Python Software Foundation (``PSF''), and the Individual or Organization (``Licensee'') accessing and otherwise using Python \version{} software in source or binary form and its associated documentation. \item Subject to the terms and conditions of this License Agreement, PSF hereby grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce, analyze, test, perform and/or display publicly, prepare derivative works, distribute, and otherwise use Python \version{} alone or in any derivative version, provided, however, that PSF's License Agreement and PSF's notice of copyright, i.e., ``Copyright \copyright{} 2001-2003 Python Software Foundation; All Rights Reserved'' are retained in Python \version{} alone or in any derivative version prepared by Licensee. \item In the event Licensee prepares a derivative work that is based on or incorporates Python \version{} or any part thereof, and wants to make the derivative work available to others as provided herein, then Licensee hereby agrees to include in any such work a brief summary of the changes made to Python \version. \item PSF is making Python \version{} available to Licensee on an ``AS IS'' basis. PSF MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, PSF MAKES NO AND DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON \version{} WILL NOT INFRINGE ANY THIRD PARTY RIGHTS. \item PSF SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON \version{} FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON \version, OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF. \item This License Agreement will automatically terminate upon a material breach of its terms and conditions. \item Nothing in this License Agreement shall be deemed to create any relationship of agency, partnership, or joint venture between PSF and Licensee. This License Agreement does not grant permission to use PSF trademarks or trade name in a trademark sense to endorse or promote products or services of Licensee, or any third party. \item By copying, installing or otherwise using Python \version, Licensee agrees to be bound by the terms and conditions of this License Agreement. \end{enumerate} \centerline{\strong{BEOPEN.COM LICENSE AGREEMENT FOR PYTHON 2.0}} \centerline{\strong{BEOPEN PYTHON OPEN SOURCE LICENSE AGREEMENT VERSION 1}} \begin{enumerate} \item This LICENSE AGREEMENT is between BeOpen.com (``BeOpen''), having an office at 160 Saratoga Avenue, Santa Clara, CA 95051, and the Individual or Organization (``Licensee'') accessing and otherwise using this software in source or binary form and its associated documentation (``the Software''). \item Subject to the terms and conditions of this BeOpen Python License Agreement, BeOpen hereby grants Licensee a non-exclusive, royalty-free, world-wide license to reproduce, analyze, test, perform and/or display publicly, prepare derivative works, distribute, and otherwise use the Software alone or in any derivative version, provided, however, that the BeOpen Python License is retained in the Software, alone or in any derivative version prepared by Licensee. \item BeOpen is making the Software available to Licensee on an ``AS IS'' basis. BEOPEN MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, BEOPEN MAKES NO AND DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE SOFTWARE WILL NOT INFRINGE ANY THIRD PARTY RIGHTS. \item BEOPEN SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF THE SOFTWARE FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THE SOFTWARE, OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF. \item This License Agreement will automatically terminate upon a material breach of its terms and conditions. \item This License Agreement shall be governed by and interpreted in all respects by the law of the State of California, excluding conflict of law provisions. Nothing in this License Agreement shall be deemed to create any relationship of agency, partnership, or joint venture between BeOpen and Licensee. This License Agreement does not grant permission to use BeOpen trademarks or trade names in a trademark sense to endorse or promote products or services of Licensee, or any third party. As an exception, the ``BeOpen Python'' logos available at http://www.pythonlabs.com/logos.html may be used according to the permissions granted on that web page. \item By copying, installing or otherwise using the software, Licensee agrees to be bound by the terms and conditions of this License Agreement. \end{enumerate} \centerline{\strong{CNRI LICENSE AGREEMENT FOR PYTHON 1.6.1}} \begin{enumerate} \item This LICENSE AGREEMENT is between the Corporation for National Research Initiatives, having an office at 1895 Preston White Drive, Reston, VA 20191 (``CNRI''), and the Individual or Organization (``Licensee'') accessing and otherwise using Python 1.6.1 software in source or binary form and its associated documentation. \item Subject to the terms and conditions of this License Agreement, CNRI hereby grants Licensee a nonexclusive, royalty-free, world-wide license to reproduce, analyze, test, perform and/or display publicly, prepare derivative works, distribute, and otherwise use Python 1.6.1 alone or in any derivative version, provided, however, that CNRI's License Agreement and CNRI's notice of copyright, i.e., ``Copyright \copyright{} 1995-2001 Corporation for National Research Initiatives; All Rights Reserved'' are retained in Python 1.6.1 alone or in any derivative version prepared by Licensee. Alternately, in lieu of CNRI's License Agreement, Licensee may substitute the following text (omitting the quotes): ``Python 1.6.1 is made available subject to the terms and conditions in CNRI's License Agreement. This Agreement together with Python 1.6.1 may be located on the Internet using the following unique, persistent identifier (known as a handle): 1895.22/1013. This Agreement may also be obtained from a proxy server on the Internet using the following URL: \url{http://hdl.handle.net/1895.22/1013}.'' \item In the event Licensee prepares a derivative work that is based on or incorporates Python 1.6.1 or any part thereof, and wants to make the derivative work available to others as provided herein, then Licensee hereby agrees to include in any such work a brief summary of the changes made to Python 1.6.1. \item CNRI is making Python 1.6.1 available to Licensee on an ``AS IS'' basis. CNRI MAKES NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE, BUT NOT LIMITATION, CNRI MAKES NO AND DISCLAIMS ANY REPRESENTATION OR WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF PYTHON 1.6.1 WILL NOT INFRINGE ANY THIRD PARTY RIGHTS. \item CNRI SHALL NOT BE LIABLE TO LICENSEE OR ANY OTHER USERS OF PYTHON 1.6.1 FOR ANY INCIDENTAL, SPECIAL, OR CONSEQUENTIAL DAMAGES OR LOSS AS A RESULT OF MODIFYING, DISTRIBUTING, OR OTHERWISE USING PYTHON 1.6.1, OR ANY DERIVATIVE THEREOF, EVEN IF ADVISED OF THE POSSIBILITY THEREOF. \item This License Agreement will automatically terminate upon a material breach of its terms and conditions. \item This License Agreement shall be governed by the federal intellectual property law of the United States, including without limitation the federal copyright law, and, to the extent such U.S. federal law does not apply, by the law of the Commonwealth of Virginia, excluding Virginia's conflict of law provisions. Notwithstanding the foregoing, with regard to derivative works based on Python 1.6.1 that incorporate non-separable material that was previously distributed under the GNU General Public License (GPL), the law of the Commonwealth of Virginia shall govern this License Agreement only as to issues arising under or with respect to Paragraphs 4, 5, and 7 of this License Agreement. Nothing in this License Agreement shall be deemed to create any relationship of agency, partnership, or joint venture between CNRI and Licensee. This License Agreement does not grant permission to use CNRI trademarks or trade name in a trademark sense to endorse or promote products or services of Licensee, or any third party. \item By clicking on the ``ACCEPT'' button where indicated, or by copying, installing or otherwise using Python 1.6.1, Licensee agrees to be bound by the terms and conditions of this License Agreement. \end{enumerate} \centerline{ACCEPT} \centerline{\strong{CWI LICENSE AGREEMENT FOR PYTHON 0.9.0 THROUGH 1.2}} Copyright \copyright{} 1991 - 1995, Stichting Mathematisch Centrum Amsterdam, The Netherlands. All rights reserved. Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of Stichting Mathematisch Centrum or CWI not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. \section{Licenses and Acknowledgements for Incorporated Software} This section is an incomplete, but growing list of licenses and acknowledgements for third-party software incorporated in the Python distribution. \subsection{Mersenne Twister} The \module{_random} module includes code based on a download from \url{http://www.math.keio.ac.jp/~matumoto/MT2002/emt19937ar.html}. The following are the verbatim comments from the original code: \begin{verbatim} A C-program for MT19937, with initialization improved 2002/1/26. Coded by Takuji Nishimura and Makoto Matsumoto. Before using, initialize the state by using init_genrand(seed) or init_by_array(init_key, key_length). Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura, All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. The names of its contributors may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Any feedback is very welcome. http://www.math.keio.ac.jp/matumoto/emt.html email: matumoto@math.keio.ac.jp \end{verbatim}