57 lines
3.8 KiB
HTML
57 lines
3.8 KiB
HTML
<?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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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2005" />
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<meta name="DC.rights.owner" content="(C) Copyright IBM Corporation 2005" />
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<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
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<meta name="DC.Type" content="concept" />
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<meta name="DC.Title" content="I/O considerations for files shared in a job" />
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<meta name="abstract" content="The server uses the same input/output area for all programs sharing the file, so the order of the operations is sequential regardless of which program does the operation." />
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<meta name="description" content="The server uses the same input/output area for all programs sharing the file, so the order of the operations is sequential regardless of which program does the operation." />
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<meta name="DC.subject" content="job, shared files in, input/output considerations, sharing file, I/O considerations, I/O considerations, shared files" />
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<meta name="keywords" content="job, shared files in, input/output considerations, sharing file, I/O considerations, I/O considerations, shared files" />
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<meta name="DC.Relation" scheme="URI" content="rbal3share.htm" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="rbal3ioc" />
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<meta name="DC.Language" content="en-us" />
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<!-- All rights reserved. Licensed Materials Property of IBM -->
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<!-- US Government Users Restricted Rights -->
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<!-- Use, duplication or disclosure restricted by -->
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<!-- GSA ADP Schedule Contract with IBM Corp. -->
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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>I/O considerations for files shared in a job</title>
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</head>
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<body id="rbal3ioc"><a name="rbal3ioc"><!-- --></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">I/O considerations for files shared in a job</h1>
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<div><p>The server uses the same input/output area for all programs sharing
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the file, so the order of the operations is sequential regardless of which
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program does the operation.</p>
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<p>For example, if Program A is reading records sequentially
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from a database file and it reads record 1 just before calling Program B,
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and Program B also reads the file sequentially, Program B reads record 2 with
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the first read operation. If Program B then ends and Program A reads the
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next record, it receives record 3. If the programs were not sharing the file,
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Program A would read record 1 and record 2, and Program B would read record
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1.</p>
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<p>For device files, the device remains in the same state as the last I/O
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operation.</p>
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<p>For display and ICF files, programs other than the first program that opens
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the file can acquire more display or program devices or release display or
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program devices already acquired to the open data path. All programs sharing
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the file have access to the newly acquired devices, and do not have access
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to any released devices.</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="rbal3share.htm" title="File management on iSeries provides several levels of support for shared files. Files can be shared among many users, many jobs, or many programs within the same job.">Share files</a></div>
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</div>
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</div>
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</body>
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</html> |