<chapter id="help-0">
  <title>Help System</title>
  <highlights>
    <para>This chapter describes the Help system in the GNOME Desktop.</para>
  </highlights>
  <sect1 id="help-1">
    <title>Introduction to the Help System</title>
    <indexterm>
      <primary>online Help</primary>
      <see>Help</see>
    </indexterm>
    <indexterm>
      <primary>Help</primary>
      <secondary>introduction</secondary>
    </indexterm>
    <para>The GNOME Desktop displays Help in the <application>Yelp</application> Help
browser. The source documents for the Help are XML files. The XML files are
written to the DocBook XML Version 4.1.2 document type definition (DTD). The
DocBook XML files are converted to HTML, and the HTML is displayed in the
Help browser. For more information on DocBook XML, see the following URL:</para>
    <literallayout>
      <ulink url="http://www.oasis-open.org/docbook/xml/">http://www.oasis-open.org/docbook/xml</ulink>
    </literallayout>
    <para>The Help system uses <firstterm>Open Source Metadata Framework</firstterm>
(OMF) files, and a cataloging system. The next sections describe OMF files
and the cataloging system.</para>
  </sect1>
  <sect1 id="help-3">
    <title>OMF Files</title>
    <indexterm>
      <primary>.omf files</primary>
      <see>OMF files</see>
    </indexterm>
    <indexterm>
      <primary>Help</primary>
      <secondary>OMF files</secondary>
    </indexterm>
    <indexterm>
      <primary>OMF files</primary>
    </indexterm>
    <para>The XML file for each manual
has an associated OMF file. The OMF file contains information about the manual
that is used by the Help browser. OMF files have a <filename>.omf</filename>
extension.</para>
    <para>When you install an application, the installation process installs an
OMF file to a directory of OMF files. If a Help document has an associated
OMF file in an OMF file directory, the Help document is displayed in the Help
browser.</para>
    <para>OMF files contain information about Help documents such as the following:</para>
    <itemizedlist>
      <listitem>
        <para>The location of the XML file for the Help document</para>
      </listitem>
      <listitem>
        <para>The title of the Help document</para>
      </listitem>
      <listitem>
        <para>A subject category to which the Help document belongs</para>
      </listitem>
    </itemizedlist>
  </sect1>
  <sect1 id="help-2">
    <title>ScrollKeeper Cataloging System</title>
    <indexterm>
      <primary>Help</primary>
      <secondary>ScrollKeeper cataloging system</secondary>
    </indexterm>
    <indexterm>
      <primary>ScrollKeeper cataloging system</primary>
    </indexterm>
    <para><application>ScrollKeeper</application> is a cataloging
system for documentation. The Help browser uses <application>ScrollKeeper</application> to catalog the manuals on the system. <application>ScrollKeeper</application> manages the information in the OMF files for the Help browser. </para>
    <para><application>ScrollKeeper</application> uses the information in the
OMF files to enable the Help browser to find Help documents on a system. When
you install an application, the installation process installs an OMF file
to a directory of OMF files. </para>
    <para><application>ScrollKeeper</application> builds a table of contents for
each Help document that has an associated OMF file. <application>ScrollKeeper</application> builds the table of contents from the XML file specified in
the OMF file. The table of contents for the Help document is displayed in
the left pane of the Help browser window, and enables users to navigate the
Help document in the left pane. The title of the document in the OMF file
is also displayed in the left pane of the Help browser window. </para>
    <para><application>ScrollKeeper</application> contains a hierarchy of subject
categories to which a Help document can belong. The Help documents are organized
into this hierarchy of subject categories in the left pane of the Help browser
window. The subject category of the document in the OMF file determines the
location of the document in the hierarchy. The hierarchy of subject categories
is defined in the following file:</para>
    <para>
      <filename>/usr/share/scrollkeeper/Templates/C/scrollkeeper_cl.xml</filename>
    </para>
    <para>The subject category of a document must correspond to a subject category
in the following file:</para>
    <para>
      <filename>/usr/share/scrollkeeper/Templates/C/scrollkeeper_cl.xml</filename>
    </para>
    <note>
      <para>If the Help document XML file is moved to a new location, then
you might need to update the location in the OMF file.</para>
    </note>
  </sect1>
</chapter>
