<chapter id="introduction">
- <!-- $Id: introduction.xml,v 1.16 2002-10-11 09:05:09 adam Exp $ -->
+ <!-- $Id: introduction.xml,v 1.39 2006-09-03 21:37:26 adam Exp $ -->
<title>Introduction</title>
- <sect1>
+ <section id="overview">
<title>Overview</title>
<para>
- <ulink url="http://www.indexdata.dk/zebra/">
- Zebra</ulink>
+ <ulink url="http://indexdata.dk/zebra/">Zebra</ulink>
is a high-performance, general-purpose structured text
- indexing and retrieval engine. It reads structured records in a
+ indexing and retrieval engine. It reads records in a
variety of input formats (eg. email, XML, MARC) and provides access
to them through a powerful combination of boolean search
expressions and relevance-ranked free-text queries.
and how to configure the server to give you the
functionality that you need.
</para>
- </sect1>
+ </section>
- <sect1 id="features">
+ <section id="features">
<title>Features</title>
<para>
<listitem>
<para>
- Very large databases: files for indexes, etc. can be
+ Very large databases: logical files can be
automatically partitioned over multiple disks.
</para>
</listitem>
<listitem>
<para>
Arbitrarily complex records. The internal data format
- is an structured format conceptually similar to XML or GRS-1,
+ is a structured format conceptually similar to XML or GRS-1,
which allows lists, nested structured data elements and
variant forms of data.
</para>
Zebra is written in portable C, so it runs on most Unix-like systems
as well as Windows NT. A binary distribution for Windows NT is
available at
- <ulink url="http://ftp.indexdata.dk/pub/zebra/win32/"/>
+ <ulink url="http://ftp.indexdata.dk/pub/zebra/win32/"/>,
+ and pre-built packages are available for
+ <!--- some Linux
+ distributions:
+ Red Hat 7.x RPMs at
+ <ulink url="http://ftp.indexdata.dk/pub/zebra/RedHat7.X/"/>
+ and Debian packages at
+ -->
+ <literal>GNU/Debian Linux</literal> at
+ <ulink url="http://ftp.indexdata.dk/pub/zebra/debian/"/>.
</para>
</listitem>
</para>
<para>
- Z39.50 protocol support:
+ <ulink url="&url.z39.50;">Z39.50</ulink> protocol support:
</para>
<para>
<para>
Protocol facilities: Init, Search, Present (retrieval),
Segmentation (support for very large records), Delete, Scan
- (index browsing), Sort, Close and some Extended Services.
+ (index browsing), Sort, Close and support for the ``update''
+ Extended Service to add or replace an existing XML record.
</para>
</listitem>
</itemizedlist>
</para>
+
+
+ <para>
+ <ulink url="&url.sru;">SRU</ulink> Web Service support:
+ </para>
+ <para>
+ <itemizedlist>
+ <listitem>
+ <para>
+ The protocol operations <literal>explain</literal>,
+ <literal>searchRetrieve</literal> and <literal>scan</literal>
+ are supported.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ <ulink url="&url.cql;">CQL</ulink> to internal query model RPN
+ conversion is supported.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Multiple XML record formats
+ for data retrieval are supported, modelled over the GRS-1, SUTRS,
+ MARC record formats. Records can be mapped between record
+ schemas on the fly. Arbitrarily complex XSLT transformations
+ can be applied during record retrieval if one uses the
+ <literal>alvis</literal> filter module.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Additional PQF query syntax for
+ <literal>searchRetrieve</literal>
+ and <literal>scan</literal> operations is supported.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+
+ </para>
+
- </sect1>
+ </section>
- <sect1 id="apps">
- <title>Applications</title>
+ <section id="introduction-apps">
+ <title>References and Zebra based Applications</title>
<para>
Zebra has been deployed in numerous applications, in both the
academic and commercial worlds, in application domains as diverse
Notable applications include the following:
</para>
- <sect2>
- <title>DADS - the DTV Article Database Service</title>
+
+ <section id="koha-ils">
+ <title>Koha free open-source ILS</title>
+ <para>
+ <ulink url="http://www.koha.org/">Koha</ulink> is a full-featured
+ open-source ILS, initially developed in
+ New Zealand by Katipo Communications Ltd, and first deployed in
+ January of 2000 for Horowhenua Library Trust. It is currently
+ maintained by a team of software providers and library technology
+ staff from around the globe.
+ </para>
+ <para>
+ <ulink url="http://liblime.com/">LibLime</ulink>,
+ a company that is marketing and supporting Koha, adds in
+ the new release of Koha 3.0 the Zebra
+ database server to drive its bibliographic database.
+ </para>
+ <para>
+ In early 2005, the Koha project development team began looking at
+ ways to improve MARC support and overcome scalability limitations
+ in the Koha 2.x series. After extensive evaluations of the best
+ of the Open Source textual database engines - including MySQL
+ full-text searching, PostgreSQL, Lucene and Plucene - the team
+ selected Zebra.
+ </para>
+ <para>
+ "Zebra completely eliminates scalability limitations, because it
+ can support tens of millions of records." explained Joshua
+ Ferraro, LibLime's Technology President and Koha's Project
+ Release Manager. "Our performance tests showed search results in
+ under a second for databases with over 5 million records on a
+ modest i386 900Mhz test server."
+ </para>
+ <para>
+ "Zebra also includes support for true boolean search expressions
+ and relevance-ranked free-text queries, both of which the Koha
+ 2.x series lack. Zebra also supports incremental and safe
+ database updates, which allow on-the-fly record
+ management. Finally, since Zebra has at its heart the Z39.50
+ protocol, it greatly improves Koha's support for that critical
+ library standard."
+ </para>
+ <para>
+ Although the bibliographic database will be moved to Zebra, Koha
+ 3.0 will continue to use a relational SQL-based database design
+ for the 'factual' database. "Relational database managers have
+ their strengths, in spite of their inability to handle large
+ numbers of bibliographic records efficiently," summed up Ferraro,
+ "We're taking the best from both worlds in our redesigned Koha
+ 3.0.
+ </para>
+ <para>
+ See also LibLime's newsletter article
+ <ulink url="http://www.liblime.com/newsletter/2006/01/features/koha-earns-its-stripes/">
+ Koha Earns its Stripes</ulink>.
+ </para>
+ </section>
+
+ <section id="emilda-ils">
+ <title>Emilda open source ILS</title>
<para>
+ <ulink url="http://www.emilda.org/">Emilda</ulink>
+ is a complete Integrated Library System, released under the
+ GNU General Public License. It has a
+ full featured Web-OPAC, allowing comprehensive system management
+ from virtually any computer with an Internet connection, has
+ template based layout allowing anyone to alter the visual
+ appearance of Emilda, and is
+ XML based language for fast and easy portability to virtually any
+ language.
+ Currently, Emilda is used at three schools in Espoo, Finland.
+ </para>
+ <para>
+ As a surplus, 100% MARC compatibility has been achieved using the
+ Zebra Server from Index Data as backend server.
+ </para>
+ </section>
+
+ <section id="reindex-ils">
+ <title>ReIndex.Net web based ILS</title>
+ <para>
+ <ulink url="http://www.reindex.net/index.php?lang=en">Reindex.net</ulink>
+ is a netbased library service offering all
+ traditional functions on a very high level plus many new
+ services. Reindex.net is a comprehensive and powerful WEB system
+ based on standards such as XML and Z39.50.
+ updates. Reindex supports MARC21, danMARC eller Dublin Core with
+ UTF8-encoding.
+ </para>
+ <para>
+ Reindex.net runs on GNU/Debian Linux with Zebra and Simpleserver
+ from Index
+ Data for bibliographic data. The relational database system
+ Sybase 9 XML is used for
+ administrative data.
+ Internally MARCXML is used for bibliographical records. Update
+ utilizes Z39.50 extended services.
+ </para>
+ </section>
+
+ <section id="dads-article-database">
+ <title>DADS - the DTV Article Database
+ Service</title>
+ <para>
DADS is a huge database of more than ten million records, totalling
over ten gigabytes of data. The records are metadata about academic
journal articles, primarily scientific; about 10% of these
</para>
<para>
More information can be found at
- <ulink url="http://www.dtv.dk/help/dads/index_e.htm"/>
+ <ulink url="http://www.dtv.dk/"/> and
+ <ulink url="http://dads.dtv.dk"/>
</para>
- </sect2>
+ </section>
- <sect2>
- <title>NLI-Z39.50 - a Natural Language Interface for Libraries</title>
+ <section id="infonet-eprints">
+ <title>Infonet Eprints</title>
<para>
- Fernuniversität Hagen in Germany have developed a natural
- language interface for access to library databases.
- <ulink url="http://ki212.fernuni-hagen.de/nli/NLIintro.html"/>
- In order to evaluate this interface for recall and precision, they
- chose Zebra as the basis for retrieval effectiveness. The Zebra
- server contains a copy of the GIRT database, consisting of more
- than 76000 records in SGML format (bibliographic records from
- social science), which are mapped to MARC for presentation.
- </para>
- <para>
- (GIRT is the German Indexing and Retrieval Testdatabase. It is a
- standard German-language test database for intelligent indexing
- and retrieval systems. See
- <ulink url="http://www.gesis.org/forschung/informationstechnologie/clef-delos.htm"/>)
- </para>
+ The InfoNet Eprints service from the
+ <ulink url="http://www.dtv.dk/">
+ Technical Knowledge Center of Denmark</ulink>
+ provides access to documents stored in
+ eprint/preprint servers and institutional research archives around
+ the world. The service is based on Open Archives Initiative metadata
+ harvesting of selected scientific archives around the world. These
+ open archives offer free and unrestricted access to their contents.
+ </para>
<para>
- Evaluation will take place as part of the TREC/CLEF campaign 2003
- <ulink url="http://clef.iei.pi.cnr.it or http://www4.eurospider.ch/CLEF/"/>
+ Infonet Eprints currently holds 1.4 million records from 16 archives.
+ The online search facility is found at
+ <ulink url="http://preprints.cvt.dk"/>.
</para>
+ </section>
+
+ <section id="alvis-project">
+ <title>Alvis</title>
<para>
- For more information, contact Johannes Leveling
- <email>Johannes.Leveling@FernUni-Hagen.De</email>
- </para>
- </sect2>
+ The <ulink url="http://www.alvis.info/alvis/">Alvis</ulink> EU
+ project run under the 6th Framework (IST-1-002068-STP)
+ is building a semantic-based peer-to-peer search engine. A
+ consortium of eleven partners from six different European
+ Community countries plus Switzerland and China contribute
+ with expertise in a broad range of specialties including network
+ topologies, routing algorithms, linguistic analysis and
+ bioinformatics.
+ </para>
+ <para>
+ The Zebra information retrieval indexing machine is used inside
+ the Alvis framework to
+ manage huge collections of natural language processed and
+ enhanced XML data, coming from a topic relevant web crawl.
+ In this application, Zebra swallows and manages 37GB of XML data
+ in about 4 hours, resulting in search times of fractions of
+ seconds.
+ </para>
+ </section>
+
- <sect2>
+ <section id="uls">
<title>ULS (Union List of Serials)</title>
<para>
- The M25-Link systems team
- (<ulink url="http://www.m25lib.ac.uk/M25link/"/>)
- are involved in a project called ULS to provide a union catalogue
- for periodicals in 21 member libraries. They do this with an
- unusual architecture which they call a
+ The M25 Systems Team
+ has created a union catalogue for the periodicals of the
+ twenty-one constituent libraries of the University of London and
+ the University of Westminster
+ (<ulink url="http://www.m25lib.ac.uk/ULS/"/>).
+ They have achieved this using an
+ unusual architecture, which they describe as a
``non-distributed virtual union catalogue''.
</para>
<para>
More information can be found at
<ulink url="http://www.m25lib.ac.uk/ULS/"/>
</para>
- </sect2>
+ </section>
+
+ <section id="nli">
+ <title>NLI-Z39.50 - a Natural Language Interface for Libraries</title>
+ <para>
+ Fernuniversität Hagen in Germany have developed a natural
+ language interface for access to library databases.
+ <!-- <ulink
+ url="http://ki212.fernuni-hagen.de/nli/NLIintro.html"/> -->
+ In order to evaluate this interface for recall and precision, they
+ chose Zebra as the basis for retrieval effectiveness. The Zebra
+ server contains a copy of the GIRT database, consisting of more
+ than 76000 records in SGML format (bibliographic records from
+ social science), which are mapped to MARC for presentation.
+ </para>
+ <para>
+ (GIRT is the German Indexing and Retrieval Testdatabase. It is a
+ standard German-language test database for intelligent indexing
+ and retrieval systems. See
+ <ulink url="http://www.gesis.org/forschung/informationstechnologie/clef-delos.htm"/>)
+ </para>
+ <para>
+ Evaluation will take place as part of the TREC/CLEF campaign 2003
+ <ulink url="http://clef.iei.pi.cnr.it"/>.
+ <!-- or <ulink url="http://www4.eurospider.ch/CLEF/"/> -->
+ </para>
+ <para>
+ For more information, contact Johannes Leveling
+ <email>Johannes.Leveling@FernUni-Hagen.De</email>
+ </para>
+ </section>
- <sect2>
+ <section id="various-web-indexes">
<title>Various web indexes</title>
<para>
Zebra has been used by a variety of institutions to construct
which is populated by the Harvest-NG web-crawling software.
</para>
<para>
- For more information, contact John Gilbertson
+ For more information on Liverpool university's intranet search
+ architecture, contact John Gilbertson
<email>jgilbert@liverpool.ac.uk</email>
</para>
- </sect2>
- </sect1>
+ <para>
+ Kang-Jin Lee
+ has recently modified the Harvest web indexer to use Zebra as
+ its native repository engine. His comments on the switch over
+ from the old engine are revealing:
+ <blockquote>
+ <para>
+ The first results after some testing with Zebra are very
+ promising. The tests were done with around 220,000 SOIF files,
+ which occupies 1.6GB of disk space.
+ </para>
+ <para>
+ Building the index from scratch takes around one hour with Zebra
+ where [old-engine] needs around five hours. While [old-engine]
+ blocks search requests when updating its index, Zebra can still
+ answer search requests.
+ [...]
+ Zebra supports incremental indexing which will speed up indexing
+ even further.
+ </para>
+ <para>
+ While the search time of [old-engine] varies from some seconds
+ to some minutes depending how expensive the query is, Zebra
+ usually takes around one to three seconds, even for expensive
+ queries.
+ [...]
+ Zebra can search more than 100 times faster than [old-engine]
+ and can process multiple search requests simultaneously
+ </para>
+ <para>
+ I am very happy to see such nice software available under GPL.
+ </para>
+ </blockquote>
+ </para>
+ </section>
+ </section>
- <sect1 id="support">
+ <section id="introduction-support">
<title>Support</title>
<para>
You can get support for Zebra from at least three sources.
</para>
<para>
First, there's the Zebra web site at
- <ulink url="http://www.indexdata.dk/zebra/"/>,
+ <ulink url="http://indexdata.dk/zebra/"/>,
which always has the most recent version available for download.
If you have a problem with Zebra, the first thing to do is see
whether it's fixed in the current release.
</para>
<para>
Second, there's the Zebra mailing list. Its home page at
- <ulink url="http://www.indexdata.dk/mailman/listinfo/zebralist"/>
+ <ulink url="http://lists.indexdata.dk/cgi-bin/mailman/listinfo/zebralist"/>
includes a complete archive of all messages that have ever been
posted on the list. The Zebra mailing list is used both for
announcements from the authors (new
releases, bug fixes, etc.) and general discussion. You are welcome
- to seek support there. Join by sending email to
- <email>zebra-request@indexdata.dk</email>. Put the word 'subscribe'
- in the body of the message.
- <!-- zebra-subscribe-###@mailman.indexdata.dk-->
+ to seek support there. Join by filling the form on the list home page.
</para>
<para>
Third, it's possible to buy a commercial support contract, with
well defined service levels and response times, from Index Data.
See
- <ulink url="http://www.indexdata.dk/support/?lang=en"/>
- <!-- ulink url="http://www.indexdata.dk/support/###"/-->
+ <ulink url="http://indexdata.dk/support/"/>
for details.
</para>
- </sect1>
+ </section>
- <sect1 id="future">
+ <section id="future">
<title>Future Directions</title>
<para>
Improved support for XML in search and retrieval. Eventually,
the goal is for Zebra to pull double duty as a flexible
information retrieval engine and high-performance XML
- repository.
+ repository. The recent addition of XPath searching is one
+ example of the kind of enhancement we're working on.
</para>
<para>
- ### Partially done.
+ There is also the experimental <literal>ALVIS XSLT</literal>
+ XML input filter, which unleashes the full power of DOM based
+ XSLT transformations during indexing and record retrieval. Work
+ on this filter has been sponsored by the ALVIS EU project
+ <ulink url="http://www.alvis.info/alvis/"/>. We expect this filter to
+ mature soon, as it is planned to be included in the version 1.4
+ release of Zebra.
</para>
</listitem>
<listitem>
<para>
- Access to search engine through SOAP/RPC API to allow the
+ Access to the search engine through SOAP/RPC API to allow the
construction of applications without requiring Z39.50 tools.
- </para>
- <para>
- ### Partially done, thanks to the new SRW/Z39.50 gateway.
+ <!--
+ This will shortly be available by means of Index Data's
+ <ulink url="http://www.loc.gov/standards/sru/srw/">SRW</ulink>-to-Z39.50 gateway, currently in beta test.
+ -->
+ Experimental support of the
+ Search/Retrieve Via URL ( <ulink url="&url.sru;">SRU</ulink>)
+ <ulink url="&url.sru;"/>
+ REST webservice, and the
+ Search/Retrieve Web Service ( <ulink url="http://www.loc.gov/standards/sru/srw/">SRW</ulink>)
+ <ulink url="http://www.loc.gov/standards/sru/srw/"/>
+ SOAP Web Service have recently been added to the YAZ/Zebra
+ combo - including server side Common Query Language (<ulink url="&url.cql;">CQL</ulink>)
+ <ulink url="&url.cql;"/> parsing
+ and configuration. It remains to find a sponsor for further testing,
+ documentation and packaging of this exiting component.
</para>
</listitem>
<listitem>
<para>
+ Support for the use of Perl both for access to the Zebra API
+ and for building extension ``plug-ins'' such as input filters.
+ The code for this has been contributed to the source tree by
+ Peter Popovics
+ <email>pop@technomat.hu</email>,
+ and is in the process of being integrated and tested.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
Improved free-text searching. We're first and foremost octet jockeys and
we're actively looking for organisations or people who'd like
to contribute experience in relevance ranking and text
or check the contact info at the end of this manual.
</para>
- </sect1>
+ </section>
</chapter>
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