GNU Free Documentation License

Ver­sion 1.2, Novem­ber 2002

Copy­right © 2000,2001,2002 Free Soft­ware Foun­da­tion, Inc.
51 Franklin St, Fifth Floor, Boston, MA 02110–1301 USA
Every­one is per­mit­ted to copy and dis­trib­ute ver­ba­tim copies
of this license doc­u­ment, but chang­ing it is not allowed.

0. PREAMBLE

The pur­pose of this License is to make a man­ual, text­book, or other func­tional and use­ful doc­u­ment “free” in the sense of free­dom: to assure every­one the effec­tive free­dom to copy and redis­trib­ute it, with or with­out mod­i­fy­ing it, either com­mer­cially or non­com­mer­cially. Sec­on­dar­ily, this License pre­serves for the author and pub­lisher a way to get credit for their work, while not being con­sid­ered respon­si­ble for mod­i­fi­ca­tions made by others.

This License is a kind of “copy­left”, which means that deriv­a­tive works of the doc­u­ment must them­selves be free in the same sense. It com­ple­ments the GNU Gen­eral Pub­lic License, which is a copy­left license designed for free software.

We have designed this License in order to use it for man­u­als for free soft­ware, because free soft­ware needs free doc­u­men­ta­tion: a free pro­gram should come with man­u­als pro­vid­ing the same free­doms that the soft­ware does. But this License is not lim­ited to soft­ware man­u­als; it can be used for any tex­tual work, regard­less of sub­ject mat­ter or whether it is pub­lished as a printed book. We rec­om­mend this License prin­ci­pally for works whose pur­pose is instruc­tion or reference.

1. APPLICABILITY AND DEFINITIONS

This License applies to any man­ual or other work, in any medium, that con­tains a notice placed by the copy­right holder say­ing it can be dis­trib­uted under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlim­ited in dura­tion, to use that work under the con­di­tions stated herein. The “Doc­u­ment”, below, refers to any such man­ual or work. Any mem­ber of the pub­lic is a licensee, and is addressed as “you”. You accept the license if you copy, mod­ify or dis­trib­ute the work in a way requir­ing per­mis­sion under copy­right law.

A “Mod­i­fied Ver­sion” of the Doc­u­ment means any work con­tain­ing the Doc­u­ment or a por­tion of it, either copied ver­ba­tim, or with mod­i­fi­ca­tions and/or trans­lated into another language.

A “Sec­ondary Sec­tion” is a named appen­dix or a front-matter sec­tion of the Doc­u­ment that deals exclu­sively with the rela­tion­ship of the pub­lish­ers or authors of the Doc­u­ment to the Document’s over­all sub­ject (or to related mat­ters) and con­tains noth­ing that could fall directly within that over­all sub­ject. (Thus, if the Doc­u­ment is in part a text­book of math­e­mat­ics, a Sec­ondary Sec­tion may not explain any math­e­mat­ics.) The rela­tion­ship could be a mat­ter of his­tor­i­cal con­nec­tion with the sub­ject or with related mat­ters, or of legal, com­mer­cial, philo­soph­i­cal, eth­i­cal or polit­i­cal posi­tion regard­ing them.

The “Invari­ant Sec­tions” are cer­tain Sec­ondary Sec­tions whose titles are des­ig­nated, as being those of Invari­ant Sec­tions, in the notice that says that the Doc­u­ment is released under this License. If a sec­tion does not fit the above def­i­n­i­tion of Sec­ondary then it is not allowed to be des­ig­nated as Invari­ant. The Doc­u­ment may con­tain zero Invari­ant Sec­tions. If the Doc­u­ment does not iden­tify any Invari­ant Sec­tions then there are none.

The “Cover Texts” are cer­tain short pas­sages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Doc­u­ment is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

A “Trans­par­ent” copy of the Doc­u­ment means a machine-readable copy, rep­re­sented in a for­mat whose spec­i­fi­ca­tion is avail­able to the gen­eral pub­lic, that is suit­able for revis­ing the doc­u­ment straight­for­wardly with generic text edi­tors or (for images com­posed of pix­els) generic paint pro­grams or (for draw­ings) some widely avail­able draw­ing edi­tor, and that is suit­able for input to text for­mat­ters or for auto­matic trans­la­tion to a vari­ety of for­mats suit­able for input to text for­mat­ters. A copy made in an oth­er­wise Trans­par­ent file for­mat whose markup, or absence of markup, has been arranged to thwart or dis­cour­age sub­se­quent mod­i­fi­ca­tion by read­ers is not Trans­par­ent. An image for­mat is not Trans­par­ent if used for any sub­stan­tial amount of text. A copy that is not “Trans­par­ent” is called “Opaque”.

Exam­ples of suit­able for­mats for Trans­par­ent copies include plain ASCII with­out markup, Tex­info input for­mat, LaTeX input for­mat, SGML or XML using a pub­licly avail­able DTD, and standard-conforming sim­ple HTML, Post­Script or PDF designed for human mod­i­fi­ca­tion. Exam­ples of trans­par­ent image for­mats include PNG, XCF and JPG. Opaque for­mats include pro­pri­etary for­mats that can be read and edited only by pro­pri­etary word proces­sors, SGML or XML for which the DTD and/or pro­cess­ing tools are not gen­er­ally avail­able, and the machine-generated HTML, Post­Script or PDF pro­duced by some word proces­sors for out­put pur­poses only.

The “Title Page” means, for a printed book, the title page itself, plus such fol­low­ing pages as are needed to hold, leg­i­bly, the mate­r­ial this License requires to appear in the title page. For works in for­mats which do not have any title page as such, “Title Page” means the text near the most promi­nent appear­ance of the work’s title, pre­ced­ing the begin­ning of the body of the text.

A sec­tion “Enti­tled XYZ” means a named sub­unit of the Doc­u­ment whose title either is pre­cisely XYZ or con­tains XYZ in paren­the­ses fol­low­ing text that trans­lates XYZ in another lan­guage. (Here XYZ stands for a spe­cific sec­tion name men­tioned below, such as “Acknowl­edge­ments”, “Ded­i­ca­tions”, “Endorse­ments”, or “His­tory”.) To “Pre­serve the Title” of such a sec­tion when you mod­ify the Doc­u­ment means that it remains a sec­tion “Enti­tled XYZ” accord­ing to this definition.

The Doc­u­ment may include War­ranty Dis­claimers next to the notice which states that this License applies to the Doc­u­ment. These War­ranty Dis­claimers are con­sid­ered to be included by ref­er­ence in this License, but only as regards dis­claim­ing war­ranties: any other impli­ca­tion that these War­ranty Dis­claimers may have is void and has no effect on the mean­ing of this License.

2. VERBATIM COPYING

You may copy and dis­trib­ute the Doc­u­ment in any medium, either com­mer­cially or non­com­mer­cially, pro­vided that this License, the copy­right notices, and the license notice say­ing this License applies to the Doc­u­ment are repro­duced in all copies, and that you add no other con­di­tions what­so­ever to those of this License. You may not use tech­ni­cal mea­sures to obstruct or con­trol the read­ing or fur­ther copy­ing of the copies you make or dis­trib­ute. How­ever, you may accept com­pen­sa­tion in exchange for copies. If you dis­trib­ute a large enough num­ber of copies you must also fol­low the con­di­tions in sec­tion 3.

You may also lend copies, under the same con­di­tions stated above, and you may pub­licly dis­play copies.

3. COPYING IN QUANTITY

If you pub­lish printed copies (or copies in media that com­monly have printed cov­ers) of the Doc­u­ment, num­ber­ing more than 100, and the Document’s license notice requires Cover Texts, you must enclose the copies in cov­ers that carry, clearly and leg­i­bly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both cov­ers must also clearly and leg­i­bly iden­tify you as the pub­lisher of these copies. The front cover must present the full title with all words of the title equally promi­nent and vis­i­ble. You may add other mate­r­ial on the cov­ers in addi­tion. Copy­ing with changes lim­ited to the cov­ers, as long as they pre­serve the title of the Doc­u­ment and sat­isfy these con­di­tions, can be treated as ver­ba­tim copy­ing in other respects.

If the required texts for either cover are too volu­mi­nous to fit leg­i­bly, you should put the first ones listed (as many as fit rea­son­ably) on the actual cover, and con­tinue the rest onto adja­cent pages.

If you pub­lish or dis­trib­ute Opaque copies of the Doc­u­ment num­ber­ing more than 100, you must either include a machine-readable Trans­par­ent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network loca­tion from which the gen­eral network-using pub­lic has access to down­load using public-standard net­work pro­to­cols a com­plete Trans­par­ent copy of the Doc­u­ment, free of added mate­r­ial. If you use the lat­ter option, you must take rea­son­ably pru­dent steps, when you begin dis­tri­b­u­tion of Opaque copies in quan­tity, to ensure that this Trans­par­ent copy will remain thus acces­si­ble at the stated loca­tion until at least one year after the last time you dis­trib­ute an Opaque copy (directly or through your agents or retail­ers) of that edi­tion to the public.

It is requested, but not required, that you con­tact the authors of the Doc­u­ment well before redis­trib­ut­ing any large num­ber of copies, to give them a chance to pro­vide you with an updated ver­sion of the Document.

4. MODIFICATIONS

You may copy and dis­trib­ute a Mod­i­fied Ver­sion of the Doc­u­ment under the con­di­tions of sec­tions 2 and 3 above, pro­vided that you release the Mod­i­fied Ver­sion under pre­cisely this License, with the Mod­i­fied Ver­sion fill­ing the role of the Doc­u­ment, thus licens­ing dis­tri­b­u­tion and mod­i­fi­ca­tion of the Mod­i­fied Ver­sion to who­ever pos­sesses a copy of it. In addi­tion, you must do these things in the Mod­i­fied Version:

* A. Use in the Title Page (and on the cov­ers, if any) a title dis­tinct from that of the Doc­u­ment, and from those of pre­vi­ous ver­sions (which should, if there were any, be listed in the His­tory sec­tion of the Doc­u­ment). You may use the same title as a pre­vi­ous ver­sion if the orig­i­nal pub­lisher of that ver­sion gives per­mis­sion.
* B. List on the Title Page, as authors, one or more per­sons or enti­ties respon­si­ble for author­ship of the mod­i­fi­ca­tions in the Mod­i­fied Ver­sion, together with at least five of the prin­ci­pal authors of the Doc­u­ment (all of its prin­ci­pal authors, if it has fewer than five), unless they release you from this require­ment.
* C. State on the Title page the name of the pub­lisher of the Mod­i­fied Ver­sion, as the pub­lisher.
* D. Pre­serve all the copy­right notices of the Doc­u­ment.
* E. Add an appro­pri­ate copy­right notice for your mod­i­fi­ca­tions adja­cent to the other copy­right notices.
* F. Include, imme­di­ately after the copy­right notices, a license notice giv­ing the pub­lic per­mis­sion to use the Mod­i­fied Ver­sion under the terms of this License, in the form shown in the Adden­dum below.
* G. Pre­serve in that license notice the full lists of Invari­ant Sec­tions and required Cover Texts given in the Document’s license notice.
* H. Include an unal­tered copy of this License.
* I. Pre­serve the sec­tion Enti­tled “His­tory”, Pre­serve its Title, and add to it an item stat­ing at least the title, year, new authors, and pub­lisher of the Mod­i­fied Ver­sion as given on the Title Page. If there is no sec­tion Enti­tled “His­tory” in the Doc­u­ment, cre­ate one stat­ing the title, year, authors, and pub­lisher of the Doc­u­ment as given on its Title Page, then add an item describ­ing the Mod­i­fied Ver­sion as stated in the pre­vi­ous sen­tence.
* J. Pre­serve the net­work loca­tion, if any, given in the Doc­u­ment for pub­lic access to a Trans­par­ent copy of the Doc­u­ment, and like­wise the net­work loca­tions given in the Doc­u­ment for pre­vi­ous ver­sions it was based on. These may be placed in the “His­tory” sec­tion. You may omit a net­work loca­tion for a work that was pub­lished at least four years before the Doc­u­ment itself, or if the orig­i­nal pub­lisher of the ver­sion it refers to gives per­mis­sion.
* K. For any sec­tion Enti­tled “Acknowl­edge­ments” or “Ded­i­ca­tions”, Pre­serve the Title of the sec­tion, and pre­serve in the sec­tion all the sub­stance and tone of each of the con­trib­u­tor acknowl­edge­ments and/or ded­i­ca­tions given therein.
* L. Pre­serve all the Invari­ant Sec­tions of the Doc­u­ment, unal­tered in their text and in their titles. Sec­tion num­bers or the equiv­a­lent are not con­sid­ered part of the sec­tion titles.
* M. Delete any sec­tion Enti­tled “Endorse­ments”. Such a sec­tion may not be included in the Mod­i­fied Ver­sion.
* N. Do not reti­tle any exist­ing sec­tion to be Enti­tled “Endorse­ments” or to con­flict in title with any Invari­ant Sec­tion.
* O. Pre­serve any War­ranty Disclaimers.

If the Mod­i­fied Ver­sion includes new front-matter sec­tions or appen­dices that qual­ify as Sec­ondary Sec­tions and con­tain no mate­r­ial copied from the Doc­u­ment, you may at your option des­ig­nate some or all of these sec­tions as invari­ant. To do this, add their titles to the list of Invari­ant Sec­tions in the Mod­i­fied Version’s license notice. These titles must be dis­tinct from any other sec­tion titles.

You may add a sec­tion Enti­tled “Endorse­ments”, pro­vided it con­tains noth­ing but endorse­ments of your Mod­i­fied Ver­sion by var­i­ous parties–for exam­ple, state­ments of peer review or that the text has been approved by an orga­ni­za­tion as the author­i­ta­tive def­i­n­i­tion of a standard.

You may add a pas­sage of up to five words as a Front-Cover Text, and a pas­sage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Mod­i­fied Ver­sion. Only one pas­sage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrange­ments made by) any one entity. If the Doc­u­ment already includes a cover text for the same cover, pre­vi­ously added by you or by arrange­ment made by the same entity you are act­ing on behalf of, you may not add another; but you may replace the old one, on explicit per­mis­sion from the pre­vi­ous pub­lisher that added the old one.

The author(s) and publisher(s) of the Doc­u­ment do not by this License give per­mis­sion to use their names for pub­lic­ity for or to assert or imply endorse­ment of any Mod­i­fied Version.

5. COMBINING DOCUMENTS

You may com­bine the Doc­u­ment with other doc­u­ments released under this License, under the terms defined in sec­tion 4 above for mod­i­fied ver­sions, pro­vided that you include in the com­bi­na­tion all of the Invari­ant Sec­tions of all of the orig­i­nal doc­u­ments, unmod­i­fied, and list them all as Invari­ant Sec­tions of your com­bined work in its license notice, and that you pre­serve all their War­ranty Disclaimers.

The com­bined work need only con­tain one copy of this License, and mul­ti­ple iden­ti­cal Invari­ant Sec­tions may be replaced with a sin­gle copy. If there are mul­ti­ple Invari­ant Sec­tions with the same name but dif­fer­ent con­tents, make the title of each such sec­tion unique by adding at the end of it, in paren­the­ses, the name of the orig­i­nal author or pub­lisher of that sec­tion if known, or else a unique num­ber. Make the same adjust­ment to the sec­tion titles in the list of Invari­ant Sec­tions in the license notice of the com­bined work.

In the com­bi­na­tion, you must com­bine any sec­tions Enti­tled “His­tory” in the var­i­ous orig­i­nal doc­u­ments, form­ing one sec­tion Enti­tled “His­tory”; like­wise com­bine any sec­tions Enti­tled “Acknowl­edge­ments”, and any sec­tions Enti­tled “Ded­i­ca­tions”. You must delete all sec­tions Enti­tled “Endorsements”.

6. COLLECTIONS OF DOCUMENTS

You may make a col­lec­tion con­sist­ing of the Doc­u­ment and other doc­u­ments released under this License, and replace the indi­vid­ual copies of this License in the var­i­ous doc­u­ments with a sin­gle copy that is included in the col­lec­tion, pro­vided that you fol­low the rules of this License for ver­ba­tim copy­ing of each of the doc­u­ments in all other respects.

You may extract a sin­gle doc­u­ment from such a col­lec­tion, and dis­trib­ute it indi­vid­u­ally under this License, pro­vided you insert a copy of this License into the extracted doc­u­ment, and fol­low this License in all other respects regard­ing ver­ba­tim copy­ing of that document.

7. AGGREGATION WITH INDEPENDENT WORKS

A com­pi­la­tion of the Doc­u­ment or its deriv­a­tives with other sep­a­rate and inde­pen­dent doc­u­ments or works, in or on a vol­ume of a stor­age or dis­tri­b­u­tion medium, is called an “aggre­gate” if the copy­right result­ing from the com­pi­la­tion is not used to limit the legal rights of the compilation’s users beyond what the indi­vid­ual works per­mit. When the Doc­u­ment is included in an aggre­gate, this License does not apply to the other works in the aggre­gate which are not them­selves deriv­a­tive works of the Document.

If the Cover Text require­ment of sec­tion 3 is applic­a­ble to these copies of the Doc­u­ment, then if the Doc­u­ment is less than one half of the entire aggre­gate, the Document’s Cover Texts may be placed on cov­ers that bracket the Doc­u­ment within the aggre­gate, or the elec­tronic equiv­a­lent of cov­ers if the Doc­u­ment is in elec­tronic form. Oth­er­wise they must appear on printed cov­ers that bracket the whole aggregate.

8. TRANSLATION

Trans­la­tion is con­sid­ered a kind of mod­i­fi­ca­tion, so you may dis­trib­ute trans­la­tions of the Doc­u­ment under the terms of sec­tion 4. Replac­ing Invari­ant Sec­tions with trans­la­tions requires spe­cial per­mis­sion from their copy­right hold­ers, but you may include trans­la­tions of some or all Invari­ant Sec­tions in addi­tion to the orig­i­nal ver­sions of these Invari­ant Sec­tions. You may include a trans­la­tion of this License, and all the license notices in the Doc­u­ment, and any War­ranty Dis­claimers, pro­vided that you also include the orig­i­nal Eng­lish ver­sion of this License and the orig­i­nal ver­sions of those notices and dis­claimers. In case of a dis­agree­ment between the trans­la­tion and the orig­i­nal ver­sion of this License or a notice or dis­claimer, the orig­i­nal ver­sion will prevail.

If a sec­tion in the Doc­u­ment is Enti­tled “Acknowl­edge­ments”, “Ded­i­ca­tions”, or “His­tory”, the require­ment (sec­tion 4) to Pre­serve its Title (sec­tion 1) will typ­i­cally require chang­ing the actual title.

9. TERMINATION

You may not copy, mod­ify, sub­li­cense, or dis­trib­ute the Doc­u­ment except as expressly pro­vided for under this License. Any other attempt to copy, mod­ify, sub­li­cense or dis­trib­ute the Doc­u­ment is void, and will auto­mat­i­cally ter­mi­nate your rights under this License. How­ever, par­ties who have received copies, or rights, from you under this License will not have their licenses ter­mi­nated so long as such par­ties remain in full compliance.

10. FUTURE REVISIONS OF THIS LICENSE

The Free Soft­ware Foun­da­tion may pub­lish new, revised ver­sions of the GNU Free Doc­u­men­ta­tion License from time to time. Such new ver­sions will be sim­i­lar in spirit to the present ver­sion, but may dif­fer in detail to address new prob­lems or con­cerns. See http://www.gnu.org/copyleft/.

Each ver­sion of the License is given a dis­tin­guish­ing ver­sion num­ber. If the Doc­u­ment spec­i­fies that a par­tic­u­lar num­bered ver­sion of this License “or any later ver­sion” applies to it, you have the option of fol­low­ing the terms and con­di­tions either of that spec­i­fied ver­sion or of any later ver­sion that has been pub­lished (not as a draft) by the Free Soft­ware Foun­da­tion. If the Doc­u­ment does not spec­ify a ver­sion num­ber of this License, you may choose any ver­sion ever pub­lished (not as a draft) by the Free Soft­ware Foundation.

ADDENDUM: How to use this License for your documents

To use this License in a doc­u­ment you have writ­ten, include a copy of the License in the doc­u­ment and put the fol­low­ing copy­right and license notices just after the title page:

Copy­right © YEAR YOUR NAME.
Per­mis­sion is granted to copy, dis­trib­ute and/or mod­ify this doc­u­ment
under the terms of the GNU Free Doc­u­men­ta­tion License, Ver­sion 1.2
or any later ver­sion pub­lished by the Free Soft­ware Foun­da­tion;
with no Invari­ant Sec­tions, no Front-Cover Texts, and no Back-Cover Texts.
A copy of the license is included in the sec­tion enti­tled
“GNU Free Doc­u­men­ta­tion License”.

If you have Invari­ant Sec­tions, Front-Cover Texts and Back-Cover Texts, replace the “with…Texts.” line with this:

with the Invari­ant Sec­tions being LIST THEIR TITLES, with the
Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.

If you have Invari­ant Sec­tions with­out Cover Texts, or some other com­bi­na­tion of the three, merge those two alter­na­tives to suit the situation.

If your doc­u­ment con­tains non­triv­ial exam­ples of pro­gram code, we rec­om­mend releas­ing these exam­ples in par­al­lel under your choice of free soft­ware license, such as the GNU Gen­eral Pub­lic License, to per­mit their use in free software.