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<!-- Copyright (C) 2003 Red Hat, Inc. --><!-- This material may be distributed only subject to the terms --><!-- and conditions set forth in the Open Publication License, v1.0 --><!-- or later (the latest version is presently available at --><!-- http://www.opencontent.org/openpub/). --><!-- Distribution of the work or derivative of the work in any --><!-- standard (paper) book form is prohibited unless prior --><!-- permission is obtained from the copyright holder. --><HTML><HEAD><TITLE>Introduction</TITLE><meta name="MSSmartTagsPreventParsing" content="TRUE"><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+"><LINKREL="HOME"TITLE="eCos Reference Manual"HREF="ecos-ref.html"><LINKREL="UP"TITLE="File System Support Infrastructure"HREF="fileio.html"><LINKREL="PREVIOUS"TITLE="File System Support Infrastructure"HREF="fileio.html"><LINKREL="NEXT"TITLE="File System Table"HREF="fileio-fstab.html"></HEAD><BODYCLASS="CHAPTER"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLESUMMARY="Header navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">eCos Reference Manual</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><AHREF="fileio.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom"></TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><AHREF="fileio-fstab.html"ACCESSKEY="N">Next</A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="CHAPTER"><H1><ANAME="FILEIO-INTRO">Chapter 19. Introduction</H1><P>This document describes the filesystem infrastructure provided ineCos. This is implemented by the FILEIO package and provides POSIXcompliant file and IO operations together with the BSD socketAPI. These APIs are described in the relevant standards and originaldocumentation and will not be described here. See <AHREF="posix-standard-support.html">Chapter 31</A> for details of which parts of thePOSIX standard are supported.</P><P>This document is concerned with the interfaces presented to clientfilesystems and network protocol stacks.</P><P>The FILEIO infrastructure consist mainly of a set of tables containingpointers to the primary interface functions of a file system. Thisapproach avoids problems of namespace pollution (for example severalfilesystems can have a function called <TTCLASS="FUNCTION">read()</TT>, so long as they arestatic). The system is also structured to eliminate the need fordynamic memory allocation.</P><P>New filesystems can be written directly to the interfaces describedhere. Existing filesystems can be ported very easily by theintroduction of a thin veneer porting layer that translates FILEIOcalls into native filesystem calls. </P><P>The term filesystem should be read fairly loosely in thisdocument. Object accessed through these interfaces could equally benetwork protocol sockets, device drivers, fifos, message queues or anyother object that can present a file-like interface.</P></DIV><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLESUMMARY="Footer navigation table"WIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><AHREF="fileio.html"ACCESSKEY="P">Prev</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="ecos-ref.html"ACCESSKEY="H">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><AHREF="fileio-fstab.html"ACCESSKEY="N">Next</A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top">File System Support Infrastructure</TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="fileio.html"ACCESSKEY="U">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top">File System Table</TD></TR></TABLE></DIV></BODY></HTML>⌨️ 快捷键说明
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