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<!--
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  * harvester.html
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  *
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  *      Authors: Duane Costa
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  *    Copyright: 2004 Regents of the University of California and the
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  *               National Center for Ecological Analysis and Synthesis,
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  *               and the University of New Mexico.
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  *  For Details: http://www.nceas.ucsb.edu/
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  *      Created: 2004 April 9
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  *      Version: 
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  *    File Info: '$ '
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  * 
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  * 
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-->
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<HTML>
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<HEAD>
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<TITLE>Metacat Harvester</TITLE>
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<link rel="stylesheet" type="text/css" href="@docrooturl@default.css">
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</HEAD> 
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<BODY>
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  <table width="100%">
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    <tr>
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      <td class="tablehead" colspan="2">
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        <p class="label">Metacat Harvester</p>
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      </td>
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      <td class="tablehead" colspan="2" align="right">
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        <a href="./properties.html">Back</a> | 
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        <a href="./metacattour.html">Home</a> | 
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        <a href="./unimplem.html">Next</a>
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      </td>
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    </tr>
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  </table>
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  <h4>Introduction</h4>
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The Metacat Harvester (henceforth referred to as "Harvester") is a
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program that automates the retrieval of EML documents from one or more sites
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and their subsequent upload (insert or update) to Metacat. Harvester uses pull
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technology to retrieve and upload documents to Metacat on a regularly
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scheduled basis.
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<P>
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Although Harvester is included with a Metacat installation (beginning with
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Metacat version 1.4.0), it is an extention to Metacat's functionality
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that may be used optionally.
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</P>
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  <h4>Definitions</h4>
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The following table defines a number of terms that are useful in discussing
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Harvester and its features.
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  <br><br>
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  <table border="1">
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    <tr>
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      <td><b>Term</b></td>
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      <td><b>Definition</b></td>
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    </tr>
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    <tr>
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      <td>Harvester</td>
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      <td>The Harvester program, a Java application that is bundled with the
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          Metacat distribution. When a user installs Metacat on a system, 
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          the Harvester program is automatically included in the 
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          installation.
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      </td>
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    </tr>
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    <tr>
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      <td>Harvester Administrator</td>
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      <td>The individual who installs and manages Harvester. Typically, this
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          would be the same individual who installs and manages Metacat at a
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          given installation.
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      </td>
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    </tr>
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    <tr>
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      <td>Harvest Site</td>
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      <td>A location from which Harvester can retrieve EML documents. A given 
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          Harvester can retrieve documents from any number of different 
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          Harvest Sites.
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      </td>
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    </tr>
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    <tr>
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      <td>Harvest</td>
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      <td>The act (by Harvester) of visiting a Harvest Site, retrieving a
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          number of EML documents, and inserting or updating the documents to 
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          Metacat.
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      </td>
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    </tr>
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    <tr>
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      <td><a name="HarvestList" >Harvest List</a></td>
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      <td>An XML document that lists a set of EML documents to be harvested. The
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          Harvest List must conform to an XML Schema, 
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          <a href="../../lib/harvester/harvestList.xsd">harvestList.xsd</a>.
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      </td>
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    </tr>
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    <tr>
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      <td>Site Contact</td>
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      <td>The individual at a particular Harvest Site who registers with 
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          Harvester, composes a Harvest List, and periodically prepares
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          the site's EML documents for retrieval and upload to Metacat.
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      </td>
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    </tr>
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    <tr>
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      <td>Harvest List URL</td>
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      <td>A URL to the Harvest List, as specified by the Site Contact. 
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          Each Harvest Site corresponds to a Harvest List URL. Harvester 
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          uses the URL to locate and read a site's Harvest List.
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      </td>
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    </tr>
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    <tr>
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      <td>Document URL</td>
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      <td>A URL to an EML document, as specified in the Harvest List.
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          The Harvest List may contain any number of Document URLs. Each
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          Document URL provides a locator to a document to be harvested.
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      </td>
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    </tr>
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    <tr>
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      <td>Harvester Registration Page</td>
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      <td>A web page that provides a means for a Site Contact
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          to register with Harvester to schedule regular harvests from the
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          site. Registration involves logging in and then specifying various
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          settings for the Harvest Site, such as the Harvest List URL, the 
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          harvest frequency, and the email address of the Site Contact.
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      </td>
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    </tr>
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  </table>
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  <h4>Managing Harvester</h4>
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  Harvester is managed by the Harvester Administrator. Typically, the same
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  individual who manages a Metacat server would also act as the Harvester
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  Administrator. The responsibilities of the Harvester Administrator include:
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    <ul>
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      <li><a href="#Configuring Harvester">Configuring Harvester</a></li>
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      <li><a href="#Running Harvester">Running Harvester</a></li>
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      <li><a href="#Reviewing Harvester">Reviewing Harvester reports to 
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      the Harvester Administrator</a></li>
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    </ul>
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  <h5><a name="Configuring Harvester">Configuring Harvester</a></h5>
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  <p>Harvester must be configured to interact with a working Metacat
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     installation. Thus, a Metacat installation that has been properly
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     configured and installed is a pre-requisite to running Harvester.
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     Additionally, Harvester has a number of settable properties that
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     control its behavior. All Harvester configuration information is managed 
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     in a single file, 
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     <a href=../../lib/metacat.properties>metacat.properties</a>, 
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     located at:
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  <pre>      METACAT_HOME/lib/metacat.properties</pre>
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     where METACAT_HOME is the top-level directory that Metacat is 
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     installed in. 
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  </p>
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  <p>Harvester properties are grouped together in 
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     <a href=../../lib/metacat.properties>metacat.properties</a>, beginning
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     after the comment line:
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  <pre><code>      # Harvester properties</code></pre>
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  </p>
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  <p>The Harvester Administrator should edit 
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     <a href=../../lib/metacat.properties>metacat.properties</a>, 
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     setting appropriate values for the <code><b>harvesterAdministrator</b></code>
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     property, the <code><b>smtpServer</b></code> property, and possibly other 
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     properties. The following table is a summary of each property and its function.
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  </p>
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  <table border="1">
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    <tr>
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      <td><b>Property</b></td>
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      <td><b>Description</b></td>
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      <td><b>Possible or default value</b></td>
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    </tr>
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    <tr>
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      <td>connectToMetacat</td>
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      <td>This property determines whether Harvester should connect to
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          Metacat to upload documents. It should be set to <code>true</code>
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          under most circumstances. Setting this property to <code>false</code>
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          can be useful for testing whether Harvester is able to retrieve 
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          documents from a site without actually connecting to Metacat to 
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          upload the documents.</td>
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      <td><code>true</code> | <code>false</code><br>
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          Default: <code>true</code>
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    </tr>
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    <tr>
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      <td>delay</td>
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      <td>The number of hours that Harvester will wait before beginning its
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          first harvest. For example, if Harvester is run at  1:00 p.m., and
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          the delay is set to 12, Harvester will begin its first harvest at 
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          1:00 a.m.</td>
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      <td>Default: 0</td>
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    </tr>
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    <tr>
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      <td>harvesterAdministrator</td>
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      <td>The email address of the Harvester Administrator. Harvester will
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          send email reports to this address after every harvest. You may
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          enter multiple email addresses by separating each address with
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          a comma or semicolon, for example, "name1@abc.edu,name2@abc.edu".
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      </td>
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      <td>An email address, or multiple email addresses separated by commas
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          or semi-colons</td>
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    </tr>
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    <tr>
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      <td>logPeriod</td>
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      <td>The number of days that Harvester should retain log entries of harvest
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          operations in the database. Harvester log entries record information
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          such as which documents were harvested, from which sites, and
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          whether any errors were encountered during the harvest. Log entries
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          older than <code>logPeriod</code> number of days are purged from the 
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          database at the end of each harvest.</td>
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      <td>Default: 90</td>
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    </tr>
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    <tr>
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      <td>maxHarvests</td>
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      <td>The maximum number of harvests that Harvester should execute before
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          shutting down. When the Harvester program is executed, it will
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          continue running until it has executed <code>maxHarvests</code>
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          number of harvests and then the program will terminate.</td>
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      <td>Default: 30</td>
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    </tr>
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    <tr>
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      <td>period</td>
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      <td>The number of hours between harvests. Harvester will run a new
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          harvest every <code>period</code> number of hours, until the 
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          <code>maxHarvests</code> number of harvests have been run.</td>
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      <td>Default: 24</td>
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    </tr>
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    <tr>
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      <td>smtpServer</td>
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      <td>The SMTP server that Harvester uses for sending email messages
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          to the Harvester Administrator and to Site Contacts.</td>
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      <td>A host name, for example: <code>somehost.institution.edu</code>
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          <br><br>
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          Default: <code>localhost</code>
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          <br><br>
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          Note that the default value will only work if the Harvester 
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          host machine has been configured as a SMTP server.
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      </td>
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    </tr>
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    <tr>
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      <td>Harvester Operation Properties (GetDocError, GetDocSuccess, etc.)</td>
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      <td>This group of properties is used by Harvester to report information
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          about the operations it performs for inclusion in log
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          entries and email messages. Under most circumstances the values 
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          of these properties should not be modified.</td>
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      <td>&nbsp;</td>
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    </tr>
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  </table>
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  <br>
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  <h5><a name="Running Harvester">Running Harvester</a></h5>
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  After Harvester has been appropriately 
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  <a href="#Configuring Harvester">configured</a>, 
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  it can be run as follows:
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  <ol>
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  <li>Open a system command window or terminal window.</li>
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  <li>Set the METACAT_HOME environment variable to the value of the Metacat
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      installation directory. Some examples follow:
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      <ul>
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        <li>On Windows:
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        <pre>set METACAT_HOME=C:\somePath\metacat</pre></li>
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        <li>On Linux/Unix (bash shell):
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        <pre>export METACAT_HOME=/home/somePath/metacat</pre></li>
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      </ul>
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  <li>cd to the following directory:
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      <ul>
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        <li>On Windows:
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        <pre>cd %METACAT_HOME%\lib\harvester</pre></li>
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        <li>On Linux/Unix:
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        <pre>cd $METACAT_HOME/lib/harvester</pre></li>
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      </ul>
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  <li>Run the appropriate Harvester shell script, as determined by the
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      operating system:
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      <ul>
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        <li>On Windows:
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        <pre>runHarvester.bat</pre></li>
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        <li>On Linux/Unix:
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        <pre>sh runHarvester.sh</pre></li>
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      </ul>
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  </li>
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  </ol>
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  <p>The Harvester application will start executing. It will begin its first
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  harvest after <code><b>delay</b></code> number of hours (as specified in the
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  <a href=../../lib/metacat.properties>metacat.properties</a>
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  file). The application will continue running a new harvest every
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  <code><b>period</b></code> number of hours until a <code><b>maxHarvests</b></code>
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  number of harvests have been completed.
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  </p>
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  <h5><a name="Reviewing Harvester">
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  Reviewing Harvester Reports to the Harvester Administrator</a></h5>
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  <P>
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  After every harvest, Harvester will send an email report to the Harvester
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  Administrator detailing the operations that were performed during the
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  harvest. The report will contain information about each of the Harvest Sites
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  that were harvested from, such as which EML documents were
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  harvested and whether any errors were encountered.
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  </P>
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  <p>
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  The harvest report will contain a list of log entries, where each log entry
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  describes an operation that was performed by Harvester. Log entries that
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  show a status value of 1 indicate that an error occurred during the
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  operation, while those that show a status value of 0 indicate that the
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  operation was completed successfully.
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  </p>
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  <P>The Harvester Administrator should review the report, paying particularly 
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  close attention to any errors that are reported and to the accompanying error
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  messages that are displayed. When errors are reported at
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  a particular site, the Harvester Administrator should contact the Site
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  Contact to determine the source of the error and its resolution. See 
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  <a href=#Reviewing>Reviewing Harvester Reports to the Site Contact</a> for a
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  description of common sources of errors at a Harvest Site.
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  </P>
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  <p>Errors that are independent of a particular site may indicate a problem 
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  with Harvester itself, Metacat, or the database connection. Refer to the
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  error message to determine the source of the error and its resolution.
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  </p>
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  <h4>Managing a Harvest Site</h4>
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  A Harvest Site is managed by a Site Contact.
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  The responsibilities of a Site Contact fall into the following categories:
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    <ul>
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      <li><a href=#Registering>Registering with Harvester</a></li>
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      <li><a href=#Composing>Composing a Harvest List</a></li>
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      <li><a href=#Preparing>Preparing EML Documents for harvest</a></li>
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      <li><a href=#Reviewing>Reviewing Harvester reports to the Site Contact</a></li>
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    </ul>
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    <h5><a name="Registering">Registering with Harvester</a></h5>
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  <p>
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  A Site Contact registers a site with Harvester by logging in to the
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  Harvester Registration page and entering several items of information
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  that Harvester needs to know about the site.
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  </p>
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  <ol>
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    <li>Logging in to the Harvester Registration Page
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  <p>
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  The Harvester Registration page is accessed from Metacat. For example, if
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  the Metacat server that you wish to register with resides at the following 
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  URL:
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  <pre>  http://somehost.somelocation.edu:8080/knb/index.jsp</pre>
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  then the Harvester Registration page would be accessed at:
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  <pre>  http://somehost.somelocation.edu:8080/knb/style/skins/knb/harvesterRegistrationLogin.html</pre>
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  </p>
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  <p>
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  After bringing up this page in your browser, login to your Metacat account 
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  by entering your username, organization, and password. For example:
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      <table bgcolor="#ffffff" border="0" cellpadding="2" width='100%' >
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        <tr > 
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          <td colspan=3 align=center >&nbsp;</td> 
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        </tr>
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        <tr > 
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          <td colspan=3 align=center >
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            <font face=verdana size=1%>
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              <b>Please  Enter Username, Organization, and Password </b>
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            </font>
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          </td> 
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        </tr>
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        <tr>
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          <td width='10%'> &nbsp;</td>
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          <td width="25%" bgcolor="#4682b4">
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            <p align="center">
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            <font color="white" face=verdana size=2%>
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            <b>Username</b>
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            </font>
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          </td>
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          <td><p><input type="text" name="uid" value="jdoe" maxlength="100" size="28"></td>
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        </tr>
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        <tr>
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          <td width='10%'> &nbsp;</td>
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          <td width="25%" bgcolor="#4682b4">
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            <p align="center">
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            <font color="white" face=verdana size=2%>
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            <b>Organization</b>
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            </font>
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          </td>
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          <td>
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            <input type="radio" name="o" value="NCEAS" checked>NCEAS
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            <input type="radio" name="o" value="LTER">LTER
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            <input type="radio" name="o" value="NRS">NRS
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            <br>
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            <input type="radio" name="o" value="PISCO">PISCO
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            <input type="radio" name="o" value="OBFS">OBFS
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            <input type="radio" name="o" value="Unaffiliated">Unaffiliated
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        </tr>
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        <tr>
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          <td width='10%'> &nbsp;</td>
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          <td bgcolor="#4682b4">
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            <p align="center">
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            <font color="white" face=verdana size=2%>
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            <b>Password</b>
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            </font>
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          </td>
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          <td><p><input type="password" name="passwd" value="*******" maxlength="60" size="28">
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          </td>
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        </tr>
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        <tr> 
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          <td colspan=3 align=center >&nbsp;</td>
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        </tr>
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      </table>
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  In some cases, a Site Contact may need to login to an anonymous account
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  rather than his or her personal account. For example, a LTER Information 
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  Manager may need to login to a dedicated account, named with a three-letter 
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  acronym, that has been set up for the LTER site. The username
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  "GCE" would be used by the LTER Information Mangager at the GCE (Georgia 
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  Coastal Ecosystems) site.
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  </p>
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    </li>
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    <li>Registering with Harvester
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  <p>
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  After logging in, you will be presented with a web form that prompts you
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  to enter information about your site and how often you want to schedule
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  harvests at your site. For example:
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      <table bgcolor="#ffffff" border="0" cellpadding="2" width='100%' >
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        <tr > 
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          <td colspan=3 align=center >&nbsp;</td> 
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        </tr>
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        <tr > 
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          <td colspan=3 align=center >
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            <font face=verdana size=1%>
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              <b>Metacat Harvester Registration </b>
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            </font>
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          </td> 
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        </tr>
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        <tr>
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          <td width='10%'> &nbsp;</td>
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          <td width="25%" bgcolor="#4682b4">
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            <p align="center">
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            <font color="white" face=verdana size=2%>
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            <b>Email address:</b>
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            </font>
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          </td>
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          <td><p><input type="text" size="55" name="uid" value="myname@institution.edu" maxlength="100" size="28"></td>
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        </tr>
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        <tr>
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          <td width='10%'> &nbsp;</td>
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          <td bgcolor="#4682b4">
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            <p align="center">
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            <font color="white" face=verdana size=2%>
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            <b>Harvest List URL:</b>
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            </font>
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          </td>
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          <td><p><input type="text" size="55" name="passwd" value="http://somehost.institution.edu/~myname/harvestList.xml" maxlength="60" size="28">
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          </td>
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        </tr>
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        <tr> 
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          <td colspan=3 align=center >&nbsp;</td>
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        </tr>
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        <tr>
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          <td width='10%'> &nbsp;</td>
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          <td bgcolor="#4682b4">
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            <p align="center">
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            <font color="white" face=verdana size=2%>
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            <b>Harvest Frequency (1-99):</b>
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            </font>
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          </td>
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          <td><p><input type="text" size="3" name="passwd" value="2" maxlength="60" size="28">
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          </td>
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        </tr>
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        <tr> 
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          <td colspan=3 align=center >&nbsp;</td>
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        </tr>
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        <tr>
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          <td width='10%'> &nbsp;</td>
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          <td width="25%" bgcolor="#4682b4">
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            <p align="center">
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            <font color="white" face=verdana size=2%>
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            <b>Unit:</b>
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            </font>
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          </td>
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          <td>
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            <input type="radio" name="o" value="days" >day(s)
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            <input type="radio" name="o" value="weeks" checked>week(s)
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            <input type="radio" name="o" value="months">month(s)
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        </tr>
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      </table>
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  <p>
460
  After values have been entered for each of these fields, click the Register 
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  button to register your site with Harvester.
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  </p>
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  <P>
464
  In the example shown above, Harvester will attempt to harvest documents from 
465
  the site once every 2 weeks, it will access the site's Harvest List at URL
466
  "http://somehost.institution.edu/~myname/harvestList.xml", and it will send
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  email reports to the Site Contact at email address "myname@institution.edu".
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  </P>
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  <P>
470
  Note that you may enter multiple email addresses by separating each
471
  address with a comma or a semi-colon. For example, 
472
  "myname@institution.edu,anothername@institution.edu".
473
  </P>
474
    </li>
475
    <li>Unregistering with Harvester
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  <p>
477
  At any time after you have registered with Harvester, you may discontinue 
478
  harvests at your site by unregistering. Simply login as described above and 
479
  then click the Unregister button. After doing so, Harvester will discontinue 
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  harvests at the site.
481
  </p>
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    </li>
483
  </ol>
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  <h5><a name="Composing">Composing a Harvest List</a></h5>
485
  <p>
486
  A Harvest List is an XML file that holds a list of EML documents to be
487
  harvested. For each EML document in the list, the following information
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  must be specified:
489
  <ul>
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    <li><code>docid</code>, which consists of the:
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      <ul>
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        <li><code>scope</code>, e.g. "demoDocument". The scope is an identifier 
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            that indicates which group of documents this document belongs to.
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        </li>
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        <li><code>identifier</code>, e.g. "1". The identifier is a number that 
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            uniquely identifies this document within the scope.
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        </li>
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        <li><code>revision</code>, e.g. "5". The revision is a number that 
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            indicates the current revision of this document.
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        </li>
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      </ul>
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    </li>
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    <li><code>documentType</code>, e.g. "eml://ecoinformatics.org/eml-2.0.0".
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        The documentType identifies the document as an EML document.</li>
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    <li><code>documentURL</code>, e.g. "http://www.lternet.edu/~dcosta/document1.xml".
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        The documentURL specifies a place where Harvester can locate 
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        and retrieve the document via HTTP.</li>
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  </ul>
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  </p>
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  <p>
511
  The contents of a Harvest List XML file must conform to a particular
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  XML Schema, as defined in file <a href="../../lib/harvester/harvestList.xsd">
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  harvestList.xsd</a>. The contents of a valid Harvest List 
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  can best be illustrated by example. The sample Harvest List
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  below contains two &lt;<code>document</code>&gt; elements that specify the 
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  information that Harvester needs to retrieve a pair of EML documents and 
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  upload them to Metacat:
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  <pre>
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&lt;?xml version="1.0" encoding="UTF-8" ?&gt;
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&lt;hrv:harvestList xmlns:hrv="eml://ecoinformatics.org/harvestList" &gt;
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    &lt;document&gt;
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        &lt;docid&gt;
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            &lt;scope&gt;demoDocument&lt;/scope&gt;
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            &lt;identifier&gt;1&lt;/identifier&gt;
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            &lt;revision&gt;5&lt;/revision&gt;
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        &lt;/docid&gt;
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        &lt;documentType&gt;eml://ecoinformatics.org/eml-2.0.0&lt;/documentType&gt;
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        &lt;documentURL&gt;http://www.lternet.edu/~dcosta/document1.xml&lt;/documentURL&gt;
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    &lt;/document&gt;
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    &lt;document&gt;
531
        &lt;docid&gt;
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            &lt;scope&gt;demoDocument&lt;/scope&gt;
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            &lt;identifier&gt;2&lt;/identifier&gt;
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            &lt;revision&gt;1&lt;/revision&gt;
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        &lt;/docid&gt;
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        &lt;documentType&gt;eml://ecoinformatics.org/eml-2.0.0&lt;/documentType&gt;
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        &lt;documentURL&gt;http://www.lternet.edu/~dcosta/document2.xml&lt;/documentURL&gt;
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    &lt;/document&gt;
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&lt;/hrv:harvestList&gt;
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  </pre>
541
  <p>
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  After editing the Harvest List, ensure that the Harvest List XML file resides
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  at the appropriate location on disk as specified by the URL that was entered
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  during the <a href=#Registering>registration</a> process.
545
  </p>
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  <p>
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  The <a href=./harvestListEditor.html>Harvest List Editor</a> is a tool that 
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  assists in composing and editing a Harvest List. (Click 
549
  <a href=./harvestListEditor.html>here</a> for additional details.)
550
  </p>
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    <h5><a name="Preparing">Preparing EML Documents for harvest</a></h5>
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  <p>
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  To prepare a set of EML documents for harvest, ensure that the following is 
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  true for each document:
555
  <ul>
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    <li>The document contains valid EML</li>
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    <li>The document is specified in a &lt;document&gt; element in the 
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        site's Harvest List, as described above</li>
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    <li>The file resides at the appropriate location on disk as specified
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        by its URL in the Harvest List</li>
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  </ul>
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  </p>
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    <h5><a name="Reviewing" >Reviewing Harvester Reports to the Site Contact</a></h5>
564
  <P>
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  After every scheduled harvest that takes place at a particular Harvest
566
  Site, Harvester will send an email report to the Site Contact detailing the 
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  operations that were performed during the harvest.
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  The report will contain information about the operations that were
569
  performed by Harvester at that site, such as 
570
  which EML documents were harvested and whether any errors were encountered.
571
  </P>
572
  <P>
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  The Site Contact should review the report, paying particularly 
574
  close attention to any errors that are reported. Errors are indicated
575
  by operations that display a status value of 1, while operations that
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  display a status value of 0 indicate that the operation completed
577
  successfully.
578
  </P>
579
  <p>
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  When errors are reported,
581
  the Site Contact should try to determine whether the source of the error
582
  is something that can be corrected at the site. Common causes of errors 
583
  might be:
584
  <ul>
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    <li>A document URL specified in the Harvest List does not match
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        the location of the actual EML file on the disk</li>
587
    <li>The Harvest List does not contain valid XML as specified in
588
        the <a href=../../lib/harvester/harvestList.xsd>harvestList.xsd</a> schema</li>
589
    <li>The URL to the Harvest List that was specified during
590
        registration with Harvester does not match the actual location of
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        the Harvest List on the disk</li>
592
    <li>An EML document that Harvester attempted to upload to Metacat does
593
        not contain valid EML</li>
594
  </ul>
595
  </P> 
596
  <p>
597
  If the Site Contact is unable to determine the cause of the error and its
598
  resolution, he or she should contact the Harvester Administrator for assistance.
599
  </p>
600
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601
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