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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><link rel="STYLESHEET" type="text/css" href="wrs.css"><title> Shared-Memory Objects </title></head><body bgcolor="FFFFFF"><p class="navbar" align="right"><a href="index.html"><img border="0" alt="[Contents]" src="icons/contents.gif"></a><a href="GuideIX.html"><img border="0" alt="[Index]" src="icons/index.gif"></a><a href="c-smo.html"><img border="0" alt="[Top]" src="icons/top.gif"></a><a href="c-smo.html"><img border="0" alt="[Prev]" src="icons/prev.gif"></a><a href="c-smo2.html"><img border="0" alt="[Next]" src="icons/next.gif"></a></p><font face="Helvetica, sans-serif" class="sans"><h3 class="H2"><i><a name="84374">6.1 Introduction</a></i></h3></font><dl class="margin"><dl class="margin"><dd><p class="Body"><a name="84376"> </a>VxMP is an optional VxWorks component that provides shared-memory objects dedicated to high-speed synchronization and communication between tasks running on separate CPUs. For information on how to install VxMP, see <i class="title">Tornado Getting Started</i>. </p><dd><p class="Body"><a name="84377"> </a><i class="term">Shared-memory objects</i> are a class of system objects that can be accessed by tasks running on different processors. They are called <i class="term">shared-memory</i> objects because the object's data structures must reside in memory accessible by all processors. Shared-memory objects are an extension of local VxWorks objects. <i class="term">Local objects</i> are only available to tasks on a single processor. VxMP supplies three kinds of shared-memory objects: </p></dl><dl class="margin"><p class="listspace"><ul class="Bullet" type="disc"><li><a name="84379"> </a>shared semaphores (binary and counting)</li></ul></p><p class="listspace"><ul class="Bullet" type="disc"><li><a name="84380"> </a>shared message queues</li></ul></p><p class="listspace"><ul class="Bullet" type="disc"><li><a name="84381"> </a>shared-memory partitions (system- and user-created partitions)</li></ul></p></dl><dl class="margin"><dd><p class="Body"><a name="84382"> </a>Shared-memory objects provide the following advantages:</p></dl><dl class="margin"><p class="listspace"><ul class="Bullet" type="disc"><li><a name="84383"> </a>A transparent interface that allows shared-memory objects to be manipulated with the same routines that are used for manipulating local objects. </li></ul></p><p class="listspace"><ul class="Bullet" type="disc"><li><a name="84384"> </a>High-speed inter-processor communication--no unnecessary packet passing is required. </li></ul></p><p class="listspace"><ul class="Bullet" type="disc"><li><a name="84385"> </a>The shared memory can reside either in dual-ported RAM or on a separate memory board.</li></ul></p></dl><dl class="margin"><dd><p class="Body"><a name="84386"> </a>The components of VxMP consist of the following: a name database (<b class="library">smNameLib</b>), shared semaphores (<b class="library">semSmLib</b>), shared message queues (<b class="library">msgQSmLib</b>), and a shared-memory allocator (<b class="library">smMemLib</b>).</p><dd><p class="Body"><a name="84387"> </a>This chapter presents a detailed description of each shared-memory object and internal considerations. It then describes configuration and troubleshooting.</p></dl></dl><a name="foot"><hr></a><p class="navbar" align="right"><a href="index.html"><img border="0" alt="[Contents]" src="icons/contents.gif"></a><a href="GuideIX.html"><img border="0" alt="[Index]" src="icons/index.gif"></a><a href="c-smo.html"><img border="0" alt="[Top]" src="icons/top.gif"></a><a href="c-smo.html"><img border="0" alt="[Prev]" src="icons/prev.gif"></a><a href="c-smo2.html"><img border="0" alt="[Next]" src="icons/next.gif"></a></p></body></html><!---by WRS Documentation (), Wind River Systems, Inc. conversion tool: Quadralay WebWorks Publisher 4.0.11 template: CSS Template, Jan 1998 - Jefro --->?? 快捷鍵說明
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