1 <?xml version="1.0" standalone="no"?>
2 <!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1//EN"
3 "http://www.oasis-open.org/docbook/xml/4.1/docbookx.dtd"
5 <!ENTITY % local SYSTEM "local.ent">
7 <!ENTITY % entities SYSTEM "entities.ent">
9 <!ENTITY % common SYSTEM "common/common.ent">
12 <!-- $Id: book.xml,v 1.13 2007-05-25 12:30:27 marc Exp $ -->
15 <title>Pazpar2 - User's Guide and Reference</title>
17 <firstname>Sebastian</firstname><surname>Hammer</surname>
20 <firstname>Adam</firstname><surname>Dickmeiss</surname>
23 <firstname>Marc</firstname><surname>Cromme</surname>
25 <releaseinfo>&version;</releaseinfo>
27 <year>©right-year;</year>
28 <holder>Index Data</holder>
32 Pazpar2 is a high-performance, user interface-independent, data
33 model-independent metasearching
34 middleware featuring merging, relevance ranking, record sorting,
38 This document is a guide and reference to Pazpar version &version;.
43 <imagedata fileref="common/id.png" format="PNG"/>
46 <imagedata fileref="common/id.eps" format="EPS"/>
53 <chapter id="introduction">
54 <title>Introduction</title>
56 Pazpar2 is a stand-alone metasearch client with a webservice API, designed
57 to be used either from a browser-based client (JavaScript, Flash, Java,
58 etc.), from from server-side code, or any combination of the two.
59 Pazpar2 is a highly optimized client designed to
60 search many resources in parallel. It implements record merging,
61 relevance-ranking and sorting by arbitrary data content, and facet
62 analysis for browsing purposes. It is designed to be data model
63 independent, and is capable of working with MARC, DublinCore, or any
64 other XML-structured response format -- XSLT is used to normalize and extract
65 data from retrieval records for display and analysis. It can be used
66 against any server which supports the Z39.50 protocol. Proprietary
67 backend modules can be used to support a large number of other protocols
68 (please contact Index Data for further information about this).
71 Additional functionality such as
72 user management, attractive displays are expected to be implemented by
73 applications that use pazpar2. Pazpar2 is user interface independent.
74 Its functionality is exposed through a simple REST-style webservice API,
75 designed to be simple to use from an Ajax-enbled browser, Flash
76 animation, Java applet, etc., or from a higher-level server-side language
77 like PHP or Java. Because session information can be shared between
78 browser-based logic and your server-side scripting, there is tremendous
79 flexibility in how you implement your business logic on top of pazpar2.
82 Once you launch a search in pazpar2, the operation continues behind the
83 scenes. Pazpar2 connects to servers, carries out searches, and
84 retrieves, deduplicates, and stores results internally. Your application
85 code may periodically inquire about the status of an ongoing operation,
86 and ask to see records or other result set facets. Result become
87 available immediately, and it is easy to build end-user interfaces which
88 feel extremely responsive, even when searching more than 100 servers
92 Pazpar2 is designed to be highly configurable. Incoming records are
93 normalized to XML/UTF-8, and then further normalized using XSLT to a
94 simple internal representation that is suitable for analysis. By
95 providing XSLT stylesheets for different kinds of result records, you
96 can tune pazpar2 to work against different kinds of information
97 retrieval servers. Finally, metadata is extracted, in a configurable
98 way, from this internal record, to support display, merging, ranking,
99 result set facets, and sorting. Pazpar2 is not bound to a specific model
100 of metadata, such as DublinCore or MARC -- by providing the right
101 configuration, it can work with a number of different kinds of data in
102 support of many different applications.
105 Pazpar2 is designed to be efficient and scalable. You can set it up to
106 search several hundred targets in parallel, or you can use it to support
107 hundreds of concurrent users. It is implemented with the same attention
108 to performance and economy that we use in our indexing engines, so that
109 you can focus on building your application, without worrying about the
110 details of metasearch logic. You can devote all of your attention to
111 usability and let pazpar2 do what it does best -- metasearch.
114 If you wish to connect to commercial or other databases which do not
115 support open standards, please contact Index Data. We have a licensing
116 agreement with a third party vendor which will enable pazpar2 to access
117 thousands of online databases, in addition the vast number of catalogs
118 and online services that support the Z39.50 protocol.
121 Pazpar2 is our attempt to re-think the traditional paradigms for
122 implementing and deploying metasearch logic, with an uncompromising
123 approach to performance, and attempting to make maximum use of the
124 capabilities of modern browsers. The demo user interface that
125 accompanies the distribution is but one example. If you think of new
126 ways of using pazpar2, we hope you'll share them with us, and if we
127 can provide assistance with regards to training, design, programming,
128 integration with different backends, hosting, or support, please don't
129 hesitate to contact us. If you'd like to see functionality in pazpar2
130 that is not there today, please don't hesitate to contact us. It may
131 already be in our development pipeline, or there might be a
132 possibility for you to help out by sponsoring development time or
133 code. Either way, get in touch and we will give you straight answers.
139 Pazpar2 is covered by the GNU license version 2.
140 See <xref linkend="license"/> for further information.
144 <chapter id="installation">
145 <title>Installation</title>
147 Pazpar2 depends on the following tools/libraries:
149 <varlistentry><term><ulink url="&url.yaz;">YAZ</ulink></term>
152 The popular Z39.50 toolkit for the C language. YAZ must be
153 compiled with Libxml2/Libxslt support.
157 <varlistentry><term><ulink url="&url.icu;">International
158 Components for Unicode (ICU)</ulink></term>
161 ICU provides Unicode support for non-english languages with
162 character sets outside the range of 7bit ASCII, like
163 Greek, Russian, German and Frensh. Pazpar2 uses the ICU
164 unicode character conversions, unicode normalization, case
165 folding and other fundamental operations needed in
166 tokenization, normalization and ranking of records.
169 Compiling, linking, and usage of the ICU libraries is optional,
170 but strongly recommended for usage in an international
178 In order to compile Pazpar2 an ANSI C compiler is
179 required. The requirements should be the same as for YAZ.
182 <section id="installation.unix">
183 <title>Installation on Unix (from Source)</title>
185 Here is a quick step-by-step guide on how to compile the
186 tools that Pazpar2 uses. Only few systems have none of the required
187 tools binary packages. If, for example, Libxml2/libxslt are already
188 installed as development packages use these.
192 Ensure that the development libraries + header files are
193 available on your system before compiling Pazpar2. For installation
194 of YAZ, refer to the YAZ installation chapter.
197 gunzip -c pazpar2-version.tar.gz|tar xf -
206 <section id="installation.debian">
207 <title>Installation on Debian GNU/Linux</title>
209 All dependencies for Pazpar2 are available as
210 <ulink url="&url.debian;">Debian</ulink>
211 packages for the sarge (stable in 2005) and etch (testing in 2005)
215 The procedures for Debian based systems, such as
216 <ulink url="&url.ubuntu;">Ubuntu</ulink> is probably similar
219 apt-get install libyaz-dev
220 apt-get install libicu36-dev
223 With these packages installed, the usual configure + make
224 procedure can be used for Pazpar2 as outlined in
225 <xref linkend="installation.unix"/>.
231 <title>Using pazpar2</title>
233 This chapter provides a general introduction to the use and
234 deployment of pazpar2.
237 <section id="architecture">
238 <title>Pazpar2 and your systems architecture</title>
240 Pazpar2 is designed to provide asynchronous, behind-the-scenes
241 metasearching functionality to your application, exposing this
242 functionality using a simple webservice API that can be accessed
243 from any number of development environments. In particular, it is
244 possible to combine pazpar2 either with your server-side dynamic
245 website scripting, with scripting or code running in the browser, or
246 with any combination of the two. Pazpar2 is an excellent tool for
247 building advanced, Ajax-based user interfaces for metasearch
248 functionality, but it isn't a requirement -- you can choose to use
249 pazpar2 entirely as a backend to your regular server-side scripting.
250 When you do use pazpar2 in conjunction
251 with browser scripting (JavaScript/Ajax, Flash, applets,
252 etc.), there are special considerations.
256 Pazpar2 implements a simple but efficient HTTP server, and it is
257 designed to interact directly with scripting running in the browser
258 for the best possible performance, and to limit overhead when
259 several browser clients generate numerous webservice requests.
260 However, it is still desirable to use a conventional webserver,
261 such as Apache, to serve up graphics, HTML documents, and
262 server-side scripting. Because the security sandbox environment of
263 most browser-side programming environments only allows communication
264 with the server from which the enclosing HTML page or object
265 originated, pazpar2 is designed so that it can act as a transparent
266 proxy in front of an existing webserver (see <xref
267 linkend="pazpar2_conf"/> for details). In this mode, all regular
268 HTTP requests are transparently passed through to your webserver,
269 while pazpar2 only intercepts search-related webservice requests.
273 If you want to expose your combined service on port 80, you can
274 either run your regular webserver on a different port, a different
275 server, or a different IP address associated with the same server.
279 Sometimes, it may be necessary to implement functionality on your
280 regular webserver that makes use of search results, for example to
281 implement data import functionality, emailing results, history
282 lists, personal citation lists, interlibrary loan functionality
283 ,etc. Fortunately, it is simple to exchange information between
284 pazpar2, your browser scripting, and backend server-side scripting.
285 You can send a session ID and possibly a record ID from your browser
286 code to your server code, and from there use pazpar2s webservice API
287 to access result sets or individual records. You could even 'hide'
288 all of pazpar2s functionality between your own API implemented on
289 the server-side, and access that from the browser or elsewhere. The
290 possibilities are just about endless.
294 <section id="data_model">
295 <title>Your data model</title>
297 Pazpar2 does not have a preconceived model of what makes up a data
298 model. There are no assumption that records have specific fields or
299 that they are organized in any particular way. The only assumption
300 is that data comes packaged in a form that the software can work
301 with (presently, that means XML or MARC), and that you can provide
302 the necessary information to massage it into pazpar2's internal
307 Handling retrieval records in pazpar2 is a two-step process. First,
308 you decide which data elements of the source record you are
309 interested in, and you specify any desired massaging or combining of
310 elements using an XSLT stylesheet (MARC records are automatically
311 normalized to MARCXML before this step). If desired, you can run
312 multiple XSLT stylesheets in series to accomplish this, but the
313 output of the last one should be a representation of the record in a
314 schema that pazpar2 understands.
318 The intermediate, internal representation of the record looks like
321 <record xmlns="http://www.indexdata.com/pazpar2/1.0"
322 mergekey="title The Shining author King, Stephen">
324 <metadata type="title">The Shining</metadata>
326 <metadata type="author">King, Stephen</metadata>
328 <metadata type="kind">ebook</metadata>
330 <!-- ... and so on -->
334 As you can see, there isn't much to it. There are really only a few
335 important elements to this file.
339 Elements should belong to the namespace
340 http://www.indexdata.com/pazpar2/1.0. If the root node contains the
341 attribute 'mergekey', then every record that generates the same
342 merge key (normalized for case differences, white space, and
343 truncation) will be joined into a cluster. In other words, you
344 decide how records are merged. If you don't include a merge key,
345 records are never merged. The 'metadata' elements provide the meat
346 of the elements -- the content. the 'type' attribute is used to
347 match each element against processing rules that determine what
348 happens to the data element next.
352 The next processing step is the extraction of metadata from the
353 intermediate representation of the record. This is governed by the
354 'metadata' elements in the 'service' section of the configuration
355 file. See <xref linkend="config-server"/> for details. The metadata
356 in the retrieval record ultimately drives merging, sorting, ranking,
357 the extraction of browse facets, and display, all configurable.
361 <section id="client">
362 <title>Client development overview</title>
364 You can use pazpar2 from any environment that allows you to use
365 webservices. The initial goal of the software was to support
366 Ajax-based applications, but there literally are no limits to what
367 you can do. You can use pazpar2 from Javascript, Flash, Java, etc.,
368 on the browser side, and from any development environment on the
369 server side, and you can pass session tokens and record IDs freely
370 around between these environments to build sophisticated applications.
371 Use your imagination.
375 The webservice API of pazpar2 is described in detail in <xref
376 linkend="pazpar2_protocol"/>.
380 In brief, you use the 'init' command to create a session, a
381 temporary workspace which carries information about the current
382 search. You start a new search using the 'search' command. Once the
383 search has been started, you can follow its progress using the
384 'stat', 'bytarget', 'termlist', or 'show' commands. Detailed records
385 can be fetched using the 'record' command.
389 <section id="nonstandard">
390 <title>Connecting to non-standard resources</title>
392 Pazpar2 uses Z39.50 as its switchboard language -- i.e. as far as it
393 is concerned, all resources speak Z39.50. It is, however, equipped
394 to handle a broad range of different server behavior, through
395 configurable query mapping and record normalization. If you develop
396 configuration, stylesheets, etc., for a new type of resources, we
397 encourage you to share your work. But you can also use pazpar2 to
398 connect to hundreds of resources that do not support standard
403 For a growing number of resources, Z39.50 is all you need. Over the
404 last few years, a number of commercial, full-text resources have
405 implemented Z39.50. These can be used through pazpar2 with little or
406 no effort. Resources that use non-standard record formats will
407 require a bit of XSLT work, but that's all.
411 But what about resources that don't support Z39.50 at all? The NISO
412 SRU (MXG) protocol is slowly gathering steam. Other resources might
413 support OpenSearch, private, XML/HTTP-based protocols, or something
414 else entirely. Some databases exist only as web user interfaces and
415 will require screen-scraping. Still others exist only as static
416 files, or perhaps as databases supporting the OAI-PMH protocol.
417 There is hope! Read on.
421 Index Data continues to advocate the support of open standards. We
422 work with database vendors to support standards, so you don't have
423 to worry about programming against non-standard services. We also
424 provide tools (see <ulink
425 url="http://www.indexdata.com/simpleserver">SimpleServer</ulink>)
426 which make it comparatively easy to build gateways against servers
427 with non-standard behavior. Again, we encourage you to share any
428 work you do in this direction.
432 But the bottom line is that working with non-standard resources in
433 metasearching is really, really hard. If you want to build a
434 project with pazpar2, and you need access to resources with
435 non-standard interfaces, we can help. We run gateways to more than
436 2,000 popular, commercial databases and other resources,
438 to plug them directly into pazpar2. For a small annual fee per
439 database, we can help you establish connections to your licensed
440 resources. Meanwhile, you can help! If you build your own
441 standards-compliant gateways, host them for others, or share the
442 code! And tell your vendors that they can save everybody money and
443 increase the appeal of their resources by supporting standards.
447 There are those who will ask us why we are using Z39.50 as our
448 switchboard langyage rather than a different protocol. Basically,
449 we believe that Z39.50 is presently the most widely implemented
450 information retrieval protocol that has the level of functionality
451 required to support a good metasearching experience (structured
452 searching, structured, well-defined results). It is also compact and
453 efficient, and there is a very broad range of tools available to
458 <section id="unicode">
459 <title>Unicode Compliance</title>
461 Pazpar2 is unicode compliant and language and locale aware to
462 the exted the used backend Z39.50 targets are. Just a few bad
463 behaving targets can spoil the search experience considerably
464 if for example Greek, Russian or otherwise non 7-bit ASCII
465 search terms are entered. In these cases some targets return
466 records irrelevant to the query, and the result screens wil be
467 cluttered with noise.
470 While noise from misbehaving targets can not be removed, it can
471 be reduced using truely unicode based ranking. This is an
472 option which is available to the system administrator if ICU
473 support is compiled into Pazpar2, see
474 <xref linkend="installation"/> for details.
477 In addition, the ICU tokenization and normalization rules must
478 be defined in the master configuration file described in
479 <xref linkend="config-server"/>.
483 </chapter> <!-- Using pazpar2 -->
485 <reference id="reference">
486 <title>Reference</title>
487 <partintro id="reference-introduction">
489 The material in this chapter is drawn directly from the individual
496 <appendix id="license"><title>License</title>
498 <section id="gpl"><title>GPL</title>
502 Copyright © ©right-year; Index Data.
506 Pazpar2 is free software; you can redistribute it and/or modify it under
507 the terms of the GNU General Public License as published by the Free
508 Software Foundation; either version 2, or (at your option) any later
513 Pazpar2 is distributed in the hope that it will be useful, but WITHOUT ANY
514 WARRANTY; without even the implied warranty of MERCHANTABILITY or
515 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
520 You should have received a copy of the GNU General Public License
521 along with Pazpar2; see the file LICENSE. If not, write to the
522 Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
527 GNU GENERAL PUBLIC LICENSE
530 Copyright (C) 1989, 1991 Free Software Foundation, Inc.
531 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
532 Everyone is permitted to copy and distribute verbatim copies
533 of this license document, but changing it is not allowed.
537 The licenses for most software are designed to take away your
538 freedom to share and change it. By contrast, the GNU General Public
539 License is intended to guarantee your freedom to share and change free
540 software--to make sure the software is free for all its users. This
541 General Public License applies to most of the Free Software
542 Foundation's software and to any other program whose authors commit to
543 using it. (Some other Free Software Foundation software is covered by
544 the GNU Library General Public License instead.) You can apply it to
547 When we speak of free software, we are referring to freedom, not
548 price. Our General Public Licenses are designed to make sure that you
549 have the freedom to distribute copies of free software (and charge for
550 this service if you wish), that you receive source code or can get it
551 if you want it, that you can change the software or use pieces of it
552 in new free programs; and that you know you can do these things.
554 To protect your rights, we need to make restrictions that forbid
555 anyone to deny you these rights or to ask you to surrender the rights.
556 These restrictions translate to certain responsibilities for you if you
557 distribute copies of the software, or if you modify it.
559 For example, if you distribute copies of such a program, whether
560 gratis or for a fee, you must give the recipients all the rights that
561 you have. You must make sure that they, too, receive or can get the
562 source code. And you must show them these terms so they know their
565 We protect your rights with two steps: (1) copyright the software, and
566 (2) offer you this license which gives you legal permission to copy,
567 distribute and/or modify the software.
569 Also, for each author's protection and ours, we want to make certain
570 that everyone understands that there is no warranty for this free
571 software. If the software is modified by someone else and passed on, we
572 want its recipients to know that what they have is not the original, so
573 that any problems introduced by others will not reflect on the original
574 authors' reputations.
576 Finally, any free program is threatened constantly by software
577 patents. We wish to avoid the danger that redistributors of a free
578 program will individually obtain patent licenses, in effect making the
579 program proprietary. To prevent this, we have made it clear that any
580 patent must be licensed for everyone's free use or not licensed at all.
582 The precise terms and conditions for copying, distribution and
585 GNU GENERAL PUBLIC LICENSE
586 TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
588 0. This License applies to any program or other work which contains
589 a notice placed by the copyright holder saying it may be distributed
590 under the terms of this General Public License. The "Program", below,
591 refers to any such program or work, and a "work based on the Program"
592 means either the Program or any derivative work under copyright law:
593 that is to say, a work containing the Program or a portion of it,
594 either verbatim or with modifications and/or translated into another
595 language. (Hereinafter, translation is included without limitation in
596 the term "modification".) Each licensee is addressed as "you".
598 Activities other than copying, distribution and modification are not
599 covered by this License; they are outside its scope. The act of
600 running the Program is not restricted, and the output from the Program
601 is covered only if its contents constitute a work based on the
602 Program (independent of having been made by running the Program).
603 Whether that is true depends on what the Program does.
605 1. You may copy and distribute verbatim copies of the Program's
606 source code as you receive it, in any medium, provided that you
607 conspicuously and appropriately publish on each copy an appropriate
608 copyright notice and disclaimer of warranty; keep intact all the
609 notices that refer to this License and to the absence of any warranty;
610 and give any other recipients of the Program a copy of this License
611 along with the Program.
613 You may charge a fee for the physical act of transferring a copy, and
614 you may at your option offer warranty protection in exchange for a fee.
616 2. You may modify your copy or copies of the Program or any portion
617 of it, thus forming a work based on the Program, and copy and
618 distribute such modifications or work under the terms of Section 1
619 above, provided that you also meet all of these conditions:
621 a) You must cause the modified files to carry prominent notices
622 stating that you changed the files and the date of any change.
624 b) You must cause any work that you distribute or publish, that in
625 whole or in part contains or is derived from the Program or any
626 part thereof, to be licensed as a whole at no charge to all third
627 parties under the terms of this License.
629 c) If the modified program normally reads commands interactively
630 when run, you must cause it, when started running for such
631 interactive use in the most ordinary way, to print or display an
632 announcement including an appropriate copyright notice and a
633 notice that there is no warranty (or else, saying that you provide
634 a warranty) and that users may redistribute the program under
635 these conditions, and telling the user how to view a copy of this
636 License. (Exception: if the Program itself is interactive but
637 does not normally print such an announcement, your work based on
638 the Program is not required to print an announcement.)
640 These requirements apply to the modified work as a whole. If
641 identifiable sections of that work are not derived from the Program,
642 and can be reasonably considered independent and separate works in
643 themselves, then this License, and its terms, do not apply to those
644 sections when you distribute them as separate works. But when you
645 distribute the same sections as part of a whole which is a work based
646 on the Program, the distribution of the whole must be on the terms of
647 this License, whose permissions for other licensees extend to the
648 entire whole, and thus to each and every part regardless of who wrote it.
650 Thus, it is not the intent of this section to claim rights or contest
651 your rights to work written entirely by you; rather, the intent is to
652 exercise the right to control the distribution of derivative or
653 collective works based on the Program.
655 In addition, mere aggregation of another work not based on the Program
656 with the Program (or with a work based on the Program) on a volume of
657 a storage or distribution medium does not bring the other work under
658 the scope of this License.
660 3. You may copy and distribute the Program (or a work based on it,
661 under Section 2) in object code or executable form under the terms of
662 Sections 1 and 2 above provided that you also do one of the following:
664 a) Accompany it with the complete corresponding machine-readable
665 source code, which must be distributed under the terms of Sections
666 1 and 2 above on a medium customarily used for software interchange; or,
668 b) Accompany it with a written offer, valid for at least three
669 years, to give any third party, for a charge no more than your
670 cost of physically performing source distribution, a complete
671 machine-readable copy of the corresponding source code, to be
672 distributed under the terms of Sections 1 and 2 above on a medium
673 customarily used for software interchange; or,
675 c) Accompany it with the information you received as to the offer
676 to distribute corresponding source code. (This alternative is
677 allowed only for noncommercial distribution and only if you
678 received the program in object code or executable form with such
679 an offer, in accord with Subsection b above.)
681 The source code for a work means the preferred form of the work for
682 making modifications to it. For an executable work, complete source
683 code means all the source code for all modules it contains, plus any
684 associated interface definition files, plus the scripts used to
685 control compilation and installation of the executable. However, as a
686 special exception, the source code distributed need not include
687 anything that is normally distributed (in either source or binary
688 form) with the major components (compiler, kernel, and so on) of the
689 operating system on which the executable runs, unless that component
690 itself accompanies the executable.
692 If distribution of executable or object code is made by offering
693 access to copy from a designated place, then offering equivalent
694 access to copy the source code from the same place counts as
695 distribution of the source code, even though third parties are not
696 compelled to copy the source along with the object code.
698 4. You may not copy, modify, sublicense, or distribute the Program
699 except as expressly provided under this License. Any attempt
700 otherwise to copy, modify, sublicense or distribute the Program is
701 void, and will automatically terminate your rights under this License.
702 However, parties who have received copies, or rights, from you under
703 this License will not have their licenses terminated so long as such
704 parties remain in full compliance.
706 5. You are not required to accept this License, since you have not
707 signed it. However, nothing else grants you permission to modify or
708 distribute the Program or its derivative works. These actions are
709 prohibited by law if you do not accept this License. Therefore, by
710 modifying or distributing the Program (or any work based on the
711 Program), you indicate your acceptance of this License to do so, and
712 all its terms and conditions for copying, distributing or modifying
713 the Program or works based on it.
715 6. Each time you redistribute the Program (or any work based on the
716 Program), the recipient automatically receives a license from the
717 original licensor to copy, distribute or modify the Program subject to
718 these terms and conditions. You may not impose any further
719 restrictions on the recipients' exercise of the rights granted herein.
720 You are not responsible for enforcing compliance by third parties to
723 7. If, as a consequence of a court judgment or allegation of patent
724 infringement or for any other reason (not limited to patent issues),
725 conditions are imposed on you (whether by court order, agreement or
726 otherwise) that contradict the conditions of this License, they do not
727 excuse you from the conditions of this License. If you cannot
728 distribute so as to satisfy simultaneously your obligations under this
729 License and any other pertinent obligations, then as a consequence you
730 may not distribute the Program at all. For example, if a patent
731 license would not permit royalty-free redistribution of the Program by
732 all those who receive copies directly or indirectly through you, then
733 the only way you could satisfy both it and this License would be to
734 refrain entirely from distribution of the Program.
736 If any portion of this section is held invalid or unenforceable under
737 any particular circumstance, the balance of the section is intended to
738 apply and the section as a whole is intended to apply in other
741 It is not the purpose of this section to induce you to infringe any
742 patents or other property right claims or to contest validity of any
743 such claims; this section has the sole purpose of protecting the
744 integrity of the free software distribution system, which is
745 implemented by public license practices. Many people have made
746 generous contributions to the wide range of software distributed
747 through that system in reliance on consistent application of that
748 system; it is up to the author/donor to decide if he or she is willing
749 to distribute software through any other system and a licensee cannot
752 This section is intended to make thoroughly clear what is believed to
753 be a consequence of the rest of this License.
755 8. If the distribution and/or use of the Program is restricted in
756 certain countries either by patents or by copyrighted interfaces, the
757 original copyright holder who places the Program under this License
758 may add an explicit geographical distribution limitation excluding
759 those countries, so that distribution is permitted only in or among
760 countries not thus excluded. In such case, this License incorporates
761 the limitation as if written in the body of this License.
763 9. The Free Software Foundation may publish revised and/or new versions
764 of the General Public License from time to time. Such new versions will
765 be similar in spirit to the present version, but may differ in detail to
766 address new problems or concerns.
768 Each version is given a distinguishing version number. If the Program
769 specifies a version number of this License which applies to it and "any
770 later version", you have the option of following the terms and conditions
771 either of that version or of any later version published by the Free
772 Software Foundation. If the Program does not specify a version number of
773 this License, you may choose any version ever published by the Free Software
776 10. If you wish to incorporate parts of the Program into other free
777 programs whose distribution conditions are different, write to the author
778 to ask for permission. For software which is copyrighted by the Free
779 Software Foundation, write to the Free Software Foundation; we sometimes
780 make exceptions for this. Our decision will be guided by the two goals
781 of preserving the free status of all derivatives of our free software and
782 of promoting the sharing and reuse of software generally.
786 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
787 FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
788 OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
789 PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
790 OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
791 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
792 TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
793 PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
794 REPAIR OR CORRECTION.
796 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
797 WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
798 REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
799 INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
800 OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
801 TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
802 YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
803 PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
804 POSSIBILITY OF SUCH DAMAGES.
806 END OF TERMS AND CONDITIONS
813 <!-- Keep this comment at the end of the file
818 sgml-minimize-attributes:nil
819 sgml-always-quote-attributes:t
822 sgml-parent-document: nil
823 sgml-local-catalogs: nil
824 sgml-namecase-general:t