74 lines
4.9 KiB
HTML
74 lines
4.9 KiB
HTML
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE 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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<html lang="en-us" xml:lang="en-us">
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="Parts of DDM: Source DDM" />
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<meta name="abstract" content="The support on the source (or local) iSeries server is started, as needed, within a source job to do DDM functions." />
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<meta name="description" content="The support on the source (or local) iSeries server is started, as needed, within a source job to do DDM functions." />
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<meta name="DC.subject" content="parts of DDM, source DDM (SDDM), DDM, parts of" />
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<meta name="keywords" content="parts of DDM, source DDM (SDDM), DDM, parts of" />
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<meta name="DC.Relation" scheme="URI" content="rbae5partsofddm.htm" />
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<meta name="DC.Relation" scheme="URI" content="rbae5xs3xsrc.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 1999, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 1999, 2006" />
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<meta name="DC.Identifier" content="rbae5partsddm" />
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<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
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<link rel="stylesheet" type="text/css" href="./ic.css" />
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<title>Parts of DDM: Source DDM</title>
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</head>
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<body id="rbae5partsddm"><a name="rbae5partsddm"><!-- --></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">Parts of DDM: Source DDM</h1>
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<div><p>The support on the source (or local) <span class="keyword">iSeries™ server</span> is
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started, as needed, within a source job to do DDM functions.</p>
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<p>The source DDM (SDDM) translates requests for remote file
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access from source server application programs into DDM requests that are
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routed to the target server for processing. The SDDM support establishes and
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manages a DDM conversation with the target server that has the desired remote
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file.</p>
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<p>When an application program first attempts to access a remote file, a search
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for the requested DDM file is done on the source server. As with local file
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processing, if the file name is not qualified with a library name, the current
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library list for the job in which the program is running is searched for the
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specified file. When the file is found, the server accesses the file, determines
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that it is a DDM file and starts the SDDM.</p>
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<p>When the SDDM is started, it checks to see if a DDM conversation is already
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active between the source job starting the SDDM and the target server identified
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by the remote location and mode values in the DDM file. If a conversation
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that can be used exists, it is used. If not, a program start request is issued
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to the appropriate target server to start a TDDM (a target job) on the target
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server to establish a DDM conversation between the SDDM and TDDM. Parameters
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that are automatically created from information in the DDM file about the
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remote file are passed when the remote server sends a program start request.</p>
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<p>After the TDDM is started, the SDDM can forward each program request to
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the target job for processing. If, for example, input/output (I/O) operations
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are to be done on a remote file, the program opens the file and then issues
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the desired operation requests. The SDDM forwards the open request and the
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TDDM opens the remote file. Then the SDDM forwards each file operation request
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to the TDDM, and both of them handle the interchange of data between the application
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program and the remote file. When a DDM function is being processed, the requesting
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program waits for the function to be completed and the results to be received,
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just as it does for local file operations.</p>
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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="rbae5partsofddm.htm" title="DDM consists of several parts to handle remote file processing among the systems using DDM.">Parts of DDM</a></div>
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</div>
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<div class="relconcepts"><strong>Related concepts</strong><br />
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<div><a href="rbae5xs3xsrc.htm" title="When an application program or user in a source server job first refers to a DDM file, several actions occur as part of processing the request on the source server.">iSeries server as the source server 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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