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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> I/O System </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-iosys.html"><img border="0" alt="[Top]" src="icons/top.gif"></a><a href="c-iosys.html"><img border="0" alt="[Prev]" src="icons/prev.gif"></a><a href="c-iosys2.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="91713">3.1 Introduction</a></i></h3></font><dl class="margin"><dl class="margin"><dd><p class="Body"><a name="83553"> </a>The VxWorks I/O system is designed to present a simple, uniform, device-independent interface to any kind of device, including:</p></dl><dl class="margin"><ul class="DashSingle" type="circle"><li><a name="83554"> </a>character-oriented devices such as terminals or communications lines</li></ul><ul class="DashSingle" type="circle"><li><a name="83555"> </a>random-access block devices such as disks</li></ul><ul class="DashSingle" type="circle"><li><a name="83556"> </a>virtual devices such as intertask <i class="term">pipes</i> and <i class="term">sockets</i></li></ul><ul class="DashSingle" type="circle"><li><a name="83557"> </a>monitor and control devices such as digital/analog I/O devices</li></ul><ul class="DashSingle" type="circle"><li><a name="83558"> </a>network devices that give access to remote devices</li></ul></dl><dl class="margin"><dd><p class="Body"><a name="83559"> </a>The VxWorks I/O system provides standard C libraries for both basic and buffered I/O. The basic I/O libraries are UNIX-compatible; the buffered I/O libraries are ANSI C-compatible. Internally, the VxWorks I/O system has a unique design that makes it faster and more flexible than most other I/O systems. These are important attributes in a real-time system.</p><dd><p class="Body"><a name="83560"> </a>This chapter first describes the nature of <i class="term">files</i> and <i class="term">devices</i>, and the user view of basic and buffered I/O. The middle section discusses the details of some specific devices. The final section is a detailed discussion of the internal structure of the VxWorks I/O system. </p><dd><p class="Body"><a name="83564"> </a><a href="c-iosys1.html#83623">Figure 3-1</a> diagrams the relationships between the different pieces of the VxWorks I/O system. All the elements of the I/O system are discussed in this chapter, except for file system routines, which are presented in <a href="c-filesys.html#84368"><i class="title">4. Local File Systems</i></a> in this manual. <div class="frame"><h4 class="EntityTitle"><a name="83623"><font face="Helvetica, sans-serif" size="-1" class="sans">Figure 3-1: Overview of the VxWorks I/O System</font></a></h4><dl class="margin"><div class="Anchor"><a name="83620"> </a><img class="figure" border="0" src="images/c-iosys0.gif"></div></dl></div></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-iosys.html"><img border="0" alt="[Top]" src="icons/top.gif"></a><a href="c-iosys.html"><img border="0" alt="[Prev]" src="icons/prev.gif"></a><a href="c-iosys2.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 --->⌨️ 快捷键说明
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