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<!DOCTYPE concept
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-00363030-AAE2-5231-8407-AC609DA0F496" xml:lang="en"><title>Backup
and Restore on Scheduled Tasks in Persistent Schedules</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>When scheduling tasks in persistent schedules, special consideration must
be given to the effects of backup and restore operations. Persistent schedules
and tasks associated with them are backed up during a backup operation. This
results in the storage of their status at the time of backup. When the data
is restored on the same phone or another phone, the persistent scheduled tasks
are recreated. This results in the overwrite of any existing persistent schedule
and task on the phone. </p>
<p> <b>Note:</b> Transient schedule and tasks are affected by the backup or
restore process. </p>
<section><title>Impact of backup and restore on persistent schedules and tasks</title> <p>State
information associated with a phone, such as date, time and conditions are
not backed up with schedules and tasks, during a phone backup. The date or
time of a phone at the time of a backup is always likely to be different from
the date or time of the target phone during restore. The conditions that are
based on <xref href="GUID-C4776034-D190-3FC4-AF45-C7F195093AC3.dita"><apiname>RProperty</apiname></xref> values that indicate the various states
of a phone might also be different between the time of backup and the time
of restore. One example is the network status, which may be unavailable at
the time of backup, but available at the time of restore. </p> <p><b>Possible
problems</b> </p> <p>When a task is scheduled in a persistent schedule, its
execution depends on a specific time or condition to become due. If the phone
is backed up before the schedule is due, the schedule information is also
part of the backup. Later, when the time or condition is satisfied, the task
is executed on the phone. But, when a phone restore is done after the task
is executed on the phone, the schedule may be due again and the task may get
executed, if the same time or condition is satisfied again. </p> <p>For example,
assume that a condition-based task is created to send an SMS when the network
is available. In addition, assume that when this task is created the network
is unavailable and a phone backup is taken. After the backup, the phone network
may become available and the SMS may be sent. In this scenario, when a phone
restore is done the SMS may be sent again when the network is available, which
can result in additional SMS costs. </p> <p><b>Recommended alternatives</b> </p> <p>The
non-repeatable nature of the tasks cannot be determined by the task scheduler
automatically, and there is no mechanism for setting per-schedule backup options.
For this reason, clients that create non-repeatable tasks must be aware of
backup and restore implications and consider this fact in their designs. </p> <p>Clients
can use transient schedules for non-repeatable tasks, which eliminates this
problem because transient schedules are not backed up or restored. If the
use of a persistent schedule is necessary, clients can choose to become backup-aware
by registering for notifications through <xref href="GUID-DC57CA2E-0EDF-3AF2-BC65-50D71665333B.dita"><apiname>CBaBackupSessionWrapper</apiname></xref> or
using the <xref href="GUID-0FE60A65-6CB6-50AB-B85F-2B60FE96ECFE.dita">Secure Backup
Engine</xref> APIs, and taking appropriate actions. These actions might be
to delete the non-repeatable task before backup or after restore, or rescheduling
it after restore to a different time for time-based schedules. </p> <p> <b>Note:</b> Any
schedule that expires or becomes ready to execute when a backup or restore
is in progress is delayed, and is only executed when the backup or restore
process is completed. </p> </section>
</conbody><related-links>
<link href="GUID-3CDCE4E0-E29D-5782-8053-B386A9E34BCC.dita"><linktext>Task Scheduler
Overview</linktext></link>
<link href="GUID-74C1C345-823C-5CD5-8FC5-214A55734E94.dita"><linktext>Developing
Programs with Task Scheduling Capabilities</linktext></link>
</related-links></concept>