77 lines
5.5 KiB
HTML
77 lines
5.5 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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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<meta name="security" content="public" />
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<meta name="Robots" content="index,follow" />
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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="reference" />
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<meta name="DC.Title" content="Example: Record format *VBS" />
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<meta name="abstract" content="This is an example of record format *VBS, which consists of graphics with explanations." />
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<meta name="description" content="This is an example of record format *VBS, which consists of graphics with explanations." />
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<meta name="DC.Relation" scheme="URI" content="formd.htm" />
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<meta name="copyright" content="(C) Copyright IBM Corporation 2004, 2006" />
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<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2004, 2006" />
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<meta name="DC.Format" content="XHTML" />
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<meta name="DC.Identifier" content="rbfvbs" />
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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>Example: Record format *VBS</title>
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</head>
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<body id="rbfvbs"><a name="rbfvbs"><!-- --></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">Example: Record format *VBS</h1>
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<div><p><span>This is an example of record format *VBS,
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which consists of graphics with explanations.</span></p>
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<div class="section"><p>Variable-length, blocked, spanned (*VBS).</p>
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</div>
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<div class="example"> <div class="fignone" id="rbfvbs__rbahh516.eps"><a name="rbfvbs__rbahh516.eps"><!-- --></a><span class="figcap">Figure 1. Variable-length, blocked, spanned
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(*VBS)</span><br /><img src="rbahh516.gif" alt="This depicts three blocks
all connected. Block 1, is comprised of XX YY, VV WW, All of Record A, VV
WW, and lastly the 1st segment of Record B. Block 1 then points to Block 2.
Block 2 is comprised of XX YY, VV WW, and the middle segment of Record B.
Block 2 then points to Block 3. Block 3 is comprised of XX YY, VV WW, the
last segment of Record B, VV WW, and all of Record C. Connected to the last
segment of Record B is TT CC and the actual data from the last segment of
B." /><br /></div>
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</div>
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<div class="example"> <div class="fignone" id="rbfvbs__rbahh517.eps"><a name="rbfvbs__rbahh517.eps"><!-- --></a><span class="figcap">Figure 2. Parts of record B</span><br /><img src="rbahh517.gif" alt="This diagram depicts the
part of Record B. The 1st part is comprised of TT CC and the 1st part of Record
B data. The 2nd part is comprised of TT CC and the 2nd part of Record B data.
The last part of Record B is comprised of TT CC and the last part of Record
B data." /><br /></div>
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</div>
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<div class="section"><p><var class="varname">XX</var> and <var class="varname">YY</var> make
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up the BDW for each data block. <var class="varname">XX</var> is the length of all
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records in each block plus the length of the BDW (4 bytes). <var class="varname">YY</var> represents
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currently reserved fields and must be 00. <var class="varname">XX</var> should be
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the actual length of the data block that is written.</p>
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</div>
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<div class="section"><p>Note that logical record B spans across three actual data blocks
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on the tape.</p>
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</div>
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<div class="section"><div class="p">Each segment of record B has its own by mapping by including the
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SDW. <var class="varname">TT</var> and <var class="varname">CC</var> make up the SDW. <var class="varname">TT</var> is
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the length of the record plus the length of the SDW (4 bytes). <var class="varname">CC</var> is
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the segment control character. The first byte of the <var class="varname">CC</var> defines
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which part of the record the segment is. The values of the control character
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can be: <ul><li> 00 binary - Complete logical record</li>
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<li> 01 binary - First segment of a multi-segment record</li>
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<li> 10 binary - Last segment of a multi-segment record</li>
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<li> 11 binary - Middle segment of a multi-segment record</li>
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</ul>
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</div>
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</div>
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<div class="section"><p>The second byte of the control character is reserved, and should
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be 0. <var class="varname">TT</var> should be the actual length of record
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data segment plus the length of the SDW (4 bytes).</p>
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</div>
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<div class="section"><p>From a user's point of view, a logical view of record B is the
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the same as other records defined above.</p>
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</div>
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<div class="example"> <div class="fignone" id="rbfvbs__rbahh518.eps"><a name="rbfvbs__rbahh518.eps"><!-- --></a><span class="figcap">Figure 3. Logical view of record B</span><br /><img src="rbahh518.gif" alt="Record B in this diagram
is comprised of VV WW and the 1st, middle, and last portions of Record B data,
concatenated." /><br /></div>
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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="formd.htm" title="Here are some examples of different record formats.">Record formats</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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