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author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2007-12-10 17:15:11 +0000 |
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committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2007-12-10 17:15:11 +0000 |
commit | 89b3ca3216c72caf0534f2f9660554198afdfe7e (patch) | |
tree | 3fb1a52ef7453a3bcfa44506b1934cc7be903cdd /nuttx/Documentation/NuttxUserGuide.html | |
parent | c63a13af0b0ab849d62890c00d09ff1fab754141 (diff) | |
download | px4-nuttx-89b3ca3216c72caf0534f2f9660554198afdfe7e.tar.gz px4-nuttx-89b3ca3216c72caf0534f2f9660554198afdfe7e.tar.bz2 px4-nuttx-89b3ca3216c72caf0534f2f9660554198afdfe7e.zip |
Release 0.3.4nuttx-3.4
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@436 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/Documentation/NuttxUserGuide.html')
-rw-r--r-- | nuttx/Documentation/NuttxUserGuide.html | 63 |
1 files changed, 55 insertions, 8 deletions
diff --git a/nuttx/Documentation/NuttxUserGuide.html b/nuttx/Documentation/NuttxUserGuide.html index 8485f287c..9e63bb0b5 100644 --- a/nuttx/Documentation/NuttxUserGuide.html +++ b/nuttx/Documentation/NuttxUserGuide.html @@ -21,7 +21,7 @@ User's Manual <p> Gregory Nutt <p> -<small>Last Update: September 23, 2007</small> +<small>Last Update: December 10, 2007</small> </center> <h1>1.0 <A NAME="Introduction">Introduction</a></h1> @@ -54,7 +54,7 @@ Gregory Nutt <li>Paragraph 2.8 <a href="#Signals">Signal Interfaces</a></li> <li>Paragraph 2.9 <a href="#Pthread">Pthread Interfaces</a></li> <li>Paragraph 2.10 <a href="#Environ">Environment Variables</a></li> - <li>Paragraph 2.11 <a href="#FileSystem">Filesystem Interfaces</a></li> + <li>Paragraph 2.11 <a href="#FileSystem">File System Interfaces</a></li> <li>Paragraph 2.12 <a href="#Network">Network Interfaces</a></li> </ul> </li> @@ -5687,11 +5687,58 @@ interface of the same name. Zero on success. </p> -<h1><a name="FileSystem">2.11 Filesystem Interfaces</a></h1> -<p> - The NuttX filesystem is very simple; it does not involve any block drivers or - particular filesystem (like FAT or EXT2 etc.). - The NuttX filesystem simply supports a set a filesystem APIs +<h1><a name="FileSystem">2.11 File System Interfaces</a></h1> + +<p><b>Overview</b>. + NuttX includes an optional, scalable file system. + This file-system may be omitted altogther; NuttX does not depend on the presence + of any file system. +</p> + +<p><b>Pseudo Root File System</b>. + Or, a simple <i>in-memory</i>, <i>psuedo</i> file system can be enabled. + This simple file system can be enabled setting the CONFIG_NFILE_DESCRIPTORS + option to a non-zero value. + This is an <i>in-memory</i> file system because it does not require any + storage medium or block driver support. + Rather, file system contents are generated on-the-fly as referenced via + standard file system operations (open, close, read, write, etc.). + In this sense, the file system is <i>psuedo</i> file system (in the + same sense that the Linux <code>/proc</code> file system is also + referred to as a psuedo file system). +</p> + +<p> + Any user supplied data or logic can be accessed via the psuedo-file system. + Built in support is provided for character and block drivers in the + <code>/dev</code> psuedo file system directory. +</p> + +<p><b>Mounted File Systems</b> + The simple in-memory file system can be extended my mounting block + devices that provide access to true file systems backed up via some + mass storage device. + NuttX supports the standard <code>mount()</code> command that allows + a block driver to be bound to a mountpoint within the psuedo file system + and to a a file system. + At present, NuttX supports only the VFAT file system. +</p> + +<p><b>Comparison to Linux</b> + From a programming perspective, the NuttX file system appears very similar + to a Linux file system. + However, there is a fundamental difference: + The NuttX root file system is a psuedo file system and true file systems may be + mounted in the psuedo file system. + In the typical Linux installation by comparison, the Linux root file system + is a true file system and psuedo file systems may be mounted in the true, + root file system. + The approach selected by NuttX is intended to support greater scalability + from the very tiny platform to the moderate platform. +</p> + +<p><b>File System Interfaces</b>. + The NuttX file system simply supports a set of standard, file system APIs (<code>open()</code>, <code>close()</code>, <code>read()</code>, <code>write</code>, etc.) and a registration mechanism that allows devices drivers to a associated with <i>nodes</i> in a file-system-like name space. @@ -6597,7 +6644,7 @@ notify a task when a message is available on a queue. <li><a href="#directoryoperations">Directory operations</a></li> <li><a href="#driveroperations">Driver operations</a></li> <li><a href="#exit">exit</a></li> - <li><a href="#FileSystem">Filesystem interfaces</a></li> + <li><a href="#FileSystem">File system interfaces</a></li> <li><a href="#getpid">getpid</a></li> <li><a href="#getsockopt">getsockopt</a></li> <li><a href="#gmtimer">gmtime_r</a></li> |