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     7     Nokia Corporation - initial contribution.

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    10 <!DOCTYPE task

    11   PUBLIC "-//OASIS//DTD DITA Task//EN" "task.dtd">

    12 <task id="GUID-0BD22FDB-1A5C-56AA-A7FC-BD2271B2F928" xml:lang="en"><title>Writing

    13 a Backup Engine Client (CSBEClient)</title><shortdesc>The Backup Engine exports <apiname>conn::CSBEClient</apiname>,

    14 which provides data to a host PC for backup and receives data from a host

    15 PC while restoring data. Device creators can call this API to write a backup

    16 server that handles PC requests for backup and restore. </shortdesc><prolog><metadata><keywords/></metadata></prolog><taskbody>

    17 <prereq><p>The <xref href="GUID-5CA933B9-7987-5DDE-AE12-B0D5AFD31451.dita">Backup

    18 Engine Overview</xref> provides an overview of the backup and restore architecture

    19 as well as components and APIs for using <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref>.

    20 It also shows that a backup server (<xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref>) interacts

    21 with a host PC and the Backup Engine. </p> <p>The <xref href="GUID-7FDD9FEC-5017-5E5D-A50A-5F343A3C7F6C.dita">Backup

    22 Engine Concepts</xref> introduces different types of backup and restore. </p> <p>The <xref href="GUID-C579E24C-2B8E-5646-B307-7967F50A0B84.dita">File Locks</xref> describes

    23 the concepts of public data and private data. </p> </prereq>

    24 <context id="GUID-039E9656-DF70-52DD-AF3A-05912737C1A9"><p>After a phone connects

    25 to a PC, the phone user can select to back up or restore data from PC-side

    26 software. The backup software on the device side responds to the requests

    27 by working with a set of components. </p> <p>Requests during a backup or a

    28 restore are usually initiated from a host PC to a backup server on a device.

    29 The backup server handles the PC requests and calls <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref> for

    30 backup and restore. The <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref> then interacts

    31 with the Backup Engine which in turn calls data owner applications for data

    32 request or supply. The backup server finally transfers the data to and from

    33 the host PC. </p> <fig id="GUID-52D747F3-9EA8-5474-B854-A00A01D6B8F1">

    34 <image href="GUID-414DD60D-C5C3-5A75-9DF7-8980F72CB485_d0e597578_href.jpg" placement="inline"/>

    35 </fig> <p>In the CSBEClient API, <codeph>RequestDataL()</codeph> and <codeph>SupplyDataL()</codeph> are

    36 two major functions for backup and restore: </p> <ul>

    37 <li id="GUID-7641D61E-215C-5326-B05B-9367DB79AC4D"><p>For a backup, the backup

    38 server calls the <codeph>CSBEClient::RequestDataL()</codeph> function which

    39 gets the data from the Backup Engine. The backup server can then transfer

    40 the data to the host for a backup. </p> </li>

    41 <li id="GUID-85B681B6-842A-5A1A-BF77-9EC83B082F56"><p>For a restore, the backup

    42 server gets the data from the host PC. The backup server then calls the <codeph>CSBEClient::SupplyDataL()</codeph> function

    43 which supplies the data to the Backup Engine for a restore. </p> </li>

    44 </ul> <p>A particular type of <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-27BF6AEB-72A0-3E39-9598-AB97BE2569FC"><apiname>conn::CSBGenericTransferType</apiname></xref> is

    45 passed to these functions depending on the data to be transferred, such as

    46 a snapshot or incremental data. Refer to the <xref href="GUID-8BFC185E-91FD-5E04-A26C-728B06F31FDD-GENID-1-7-1-23-1-1-4-1-3-1-6-1-6-1.dita">Creating

    47 transfer types</xref> section for an example. </p><p> The backup and restore

    48 sections below describe the <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref> function calls.

    49 The sequence of the calls depends on the requests from the host PC and the

    50 backup server, but the recommended sequence is listed below.</p> </context>

    51 <steps-unordered id="GUID-23CB37EE-9978-5FCF-BBC2-B532FA1323FC">

    52 <step id="GUID-8298F87B-6603-57DB-B2F4-08615F61442D"><cmd/>

    53 

    54 <info><xref href="GUID-F40BA7EA-AF7E-5BCF-96DD-9C4D8E947F0C.dita">Writing a CSBEClient

    55 for Backup</xref> describes the sequence of <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref> functions

    56 call for partial and incremental data backup. </info>

    57 </step>

    58 <step id="GUID-61CD02CF-7592-5F6E-9943-98BEB5397E69"><cmd/>

    59 <info><xref href="GUID-A5ED089C-8831-5E25-AE7C-8E6F1C21D3BE.dita">Writing a CSBEClient

    60 for Restore</xref>  describes the sequence of <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref> functions

    61 call for partial and incremental data restore. </info>

    62 </step>

    63 <step id="GUID-151F94B7-4A9F-5C58-8AE0-B15C83025801"><cmd/>

    64 <info><xref href="GUID-8BFC185E-91FD-5E04-A26C-728B06F31FDD-GENID-1-7-1-23-1-1-4-1-3-1-6-1-6-1.dita">Creating Transfer

    65 Types</xref> describes how to create a particular <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-27BF6AEB-72A0-3E39-9598-AB97BE2569FC"><apiname>conn::CSBGenericTransferType</apiname></xref> transfer

    66 data type. The data type is passed to the <xref href="GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2.dita#GUID-169BB4E2-5B0E-3719-A7B8-A3C0AAA602E2/GUID-FB671D02-0F15-396F-9FB7-EE3E9372093C"><apiname>conn::CSBEClient</apiname></xref> to

    67 transfer the data from or to the Backup Engine. </info>

    68 </step>

    69 </steps-unordered>

    70 </taskbody><related-links>

    71 <link href="GUID-5CA933B9-7987-5DDE-AE12-B0D5AFD31451.dita"><linktext>Backup Engine

    72 Overview</linktext></link>

    73 <link href="GUID-743D2832-E73A-5184-A85D-306B2A6FFACC.dita"><linktext>Active Backup

    74 Client</linktext></link>

    75 </related-links></task>