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+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-3CDCE4E0-E29D-5782-8053-B386A9E34BCC" xml:lang="en"><title>Task
+Scheduler Overview</title><abstract><p>The Task Scheduler enables clients to schedule tasks for time-based
+and condition-based execution. The Task Scheduler is a <xref href="GUID-A3449F37-89BB-5208-8FD5-F4DF73F7E71A.dita">Startup
+State Aware </xref> component. This ensures no task is initiated
+before all system-level services are up and running. </p><p>The time or condition
+for task execution is defined in a schedule. Schedules and tasks can be persistent
+or transient. Schedules can be created, edited and deleted. </p><p> The Task
+Scheduler participates in a system-wide backup or restore operation initiated
+by the <xref href="GUID-EB624E33-0FB1-33BB-A423-0CB3C0A71548.dita"><apiname>Secure Backup Engine</apiname></xref> as a passive backup client.
+This ensures the persistent schedules are backed up and restored.</p></abstract><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section><title>Required background</title> <p>In a condition-based schedule,
+a condition can be user-defined or system condition. User defined conditions
+are published using Publish and Subscribe keys. For more information about
+Publish and Subscribe concept refer <xref href="GUID-A81C65CF-CF4E-571C-8080-9D387F46AAD6.dita"> Publish
+and Subscribe.</xref>  </p> </section>
+<section><title>Key concepts and terms</title> <dl>
+<dlentry>
+<dt>Task</dt>
+<dd><p>The execution of an application or program. </p> </dd>
+</dlentry>
+<dlentry>
+<dt> Schedule</dt>
+<dd><p>A plan for performing a task. </p> </dd>
+</dlentry>
+<dlentry>
+<dt>Persistent Schedule</dt>
+<dd><p>The lifetime of a persistent schedule is not limited to the lifetime
+of the tasks associated with it. </p> </dd>
+</dlentry>
+<dlentry>
+<dt>Transient Schedule</dt>
+<dd><p>A Transient schedule is created with a new scheduled task and is destroyed
+on task destruction. Transient schedules and tasks are not persisted on disk-based
+storage. </p> </dd>
+</dlentry>
+<dlentry>
+<dt>Time-based Schedule</dt>
+<dd><p>A Time-based schedule contains one or more tasks that are due for execution
+at a specified time. </p> </dd>
+</dlentry>
+<dlentry>
+<dt>Condition-based Schedule</dt>
+<dd><p>A condition-based schedule contains one or more tasks which are executed
+when either a set of certin Publish and Subscribe conditions are met or a
+default time-out is reached. </p> </dd>
+</dlentry>
+<dlentry>
+<dt> Home-Time based Schedule</dt>
+<dd><p>A home-time based schedule occur at a given local time. Local time
+typically includes changes for time zone and DST. These schedules are referred
+to as ‘floating’ schedules. </p> </dd>
+</dlentry>
+<dlentry>
+<dt>Daylight Saving Time (DST)</dt>
+<dd><p>Daylight Saving Time (or summertime as it is called in many countries)
+is a way of utilizing more daylight by advancing the local time by one hour
+during the summer. </p> </dd>
+</dlentry>
+<dlentry>
+<dt> Coordinated Universal Time (UTC) </dt>
+<dd><p>UTC is independent of location. UTC-based schedules occur at a given
+UTC time regardless of the local time. </p> </dd>
+</dlentry>
+</dl> </section>
+<section><title>Architecture</title> <p>The task scheduler is a permanent
+server. It is automatically started when the phone boots or reboots and does
+not shutdown while the phone is running. If the server fails, and cannot be
+automatically restarted, the phone restarts automatically. Persistent schedules
+are stored the permanent file store. Transient schedules are lost if the server
+fails. </p> <p>A client must register with the task scheduler before it can
+schedule a task. </p> </section>
+<section><title>APIs</title> <p>The main APIs of the task scheduler are: </p> <table id="GUID-827B6362-E8E1-5EA3-937F-E655CCEB97D2">
+<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>
+<thead>
+<row>
+<entry>API</entry>
+<entry>Description</entry>
+</row>
+</thead>
+<tbody>
+<row>
+<entry><p> <xref href="GUID-049FF2D7-8444-3E87-BF2F-DD0EA9B10ED0.dita"><apiname>CScheduledTask</apiname></xref>  </p> </entry>
+<entry><p>A scheduled task </p> </entry>
+</row>
+<row>
+<entry><p> <xref href="GUID-6E138B87-ED51-3C72-9075-8D7F887FA7B1.dita"><apiname>RScheduler</apiname></xref>  </p> </entry>
+<entry><p>The client side interface to the Task Scheduler. </p> </entry>
+</row>
+</tbody>
+</tgroup>
+</table> </section>
+<section><title>Typical uses</title> <p>The main uses of the task scheduler
+are: </p> <ul>
+<li id="GUID-5A6433D7-73AC-5FCA-AF14-60DFFBA69545"><p>Schedule a sequence
+of tasks to be executed based on time. </p> </li>
+<li id="GUID-F8F7BF9A-A42F-5C1F-A6E3-4DEA2202B4FE"><p>Schedule a sequence
+of tasks to be executed based on conditions. </p> </li>
+</ul> <p>For more information about using the task scheduler APIs, see the <xref href="GUID-74C1C345-823C-5CD5-8FC5-214A55734E94.dita">Developing Programs with
+Task Scheduling Capabilities</xref> section. </p> </section>
+<section><title>See also</title> <p><xref href="GUID-00363030-AAE2-5231-8407-AC609DA0F496.dita">Backup
+and Restore on Scheduled Tasks in Persistent Schedules</xref>  </p> </section>
+</conbody></concept>
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