65 lines
4.2 KiB
HTML
65 lines
4.2 KiB
HTML
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PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<meta name="DC.Title" content="DDM conversation length considerations" />
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<meta name="abstract" content="Consider these items regarding the length of conversations when using DDM." />
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<meta name="description" content="Consider these items regarding the length of conversations when using DDM." />
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<meta name="DC.subject" content="conversation length, within source job, DDM architecture, extensions to, performance considerations, System/38, extensions" />
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<meta name="keywords" content="conversation length, within source job, DDM architecture, extensions to, performance considerations, System/38, extensions" />
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<title>DDM conversation length considerations</title>
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</head>
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<body id="rbae5length"><a name="rbae5length"><!-- --></a>
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<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
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<h1 class="topictitle1">DDM conversation length considerations</h1>
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<div><p>Consider these items regarding the length of conversations
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when using DDM.</p>
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<div class="section"><ul><li>Within a source job, if it is likely that a DDM conversation will be used
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by more than one program or DDM file, *KEEP is the value that should be specified
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for the DDMCNV job attribute. This saves the time and resources needed to
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start a target job (TDDM) each time a DDM file is accessed for the same location
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and mode combination within the source job.</li>
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<li>There is significant server and communications line overhead when a target
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DDM manager is started. The processing includes the APPC program start request,
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server type identification, and file open processing. However, if it is not
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necessary to keep the conversation active, *DROP should be specified for DDMCNV.
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When the local DDM file is closed, the session being used is released for
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use by other jobs using DDM or other APPC functions, such as SNADS and display
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station pass-through, to the same remote server.</li>
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<li>When the source and target servers are <span class="keyword">iSeries™ server</span>s
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or <span class="keyword">System/38™</span>, the file input
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and output requests made by an application program use a form of DDM support
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that minimizes the amount of time needed to code and decode each request.
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This is accomplished by <span class="keyword">System/38</span> extensions
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to the DDM architecture. <p>When the source and target servers are neither
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an <span class="keyword">iSeries server</span> nor a <span class="keyword">System/38</span>, then <span class="keyword">System/38</span> extensions
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to the DDM architecture are not used.</p>
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</li>
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</ul>
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</div>
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</div>
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<div>
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<div class="familylinks">
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<div class="parentlink"><strong>Parent topic:</strong> <a href="rbae5perfcon.htm" title="These topics provide information to help you improve performance when using DDM and also provide some information about when to use something other than DDM to accomplish some functions.">Performance considerations for DDM</a></div>
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</div>
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</div>
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</body>
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</html>
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