44 lines
2.0 KiB
ReStructuredText
44 lines
2.0 KiB
ReStructuredText
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=================
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NuttX File System
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=================
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**Overview**. NuttX includes an optional, scalable file system.
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This file-system may be omitted altogether; NuttX does not depend
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on the presence of any file system.
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**Pseudo Root File System**. A simple *in-memory*, *pseudo* file
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system can be enabled by default. This is an *in-memory* file
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system because it does not require any storage medium or block
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driver support. Rather, file system contents are generated
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on-the-fly as referenced via standard file system operations
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(open, close, read, write, etc.). In this sense, the file system
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is *pseudo* file system (in the same sense that the Linux
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``/proc`` file system is also referred to as a pseudo file
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system).
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Any user supplied data or logic can be accessed via the
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pseudo-file system. Built in support is provided for character and
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block `drivers <#DeviceDrivers>`__ in the ``/dev`` pseudo file
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system directory.
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**Mounted File Systems** The simple in-memory file system can be
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extended my mounting block devices that provide access to true
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file systems backed up via some mass storage device. NuttX
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supports the standard ``mount()`` command that allows a block
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driver to be bound to a mountpoint within the pseudo file system
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and to a file system. At present, NuttX supports the standard VFAT
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and ROMFS file systems, a special, wear-leveling NuttX FLASH File
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System (NXFFS), as well as a Network File System client (NFS
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version 3, UDP).
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**Comparison to Linux** From a programming perspective, the NuttX
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file system appears very similar to a Linux file system. However,
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there is a fundamental difference: The NuttX root file system is a
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pseudo file system and true file systems may be mounted in the
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pseudo file system. In the typical Linux installation by
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comparison, the Linux root file system is a true file system and
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pseudo file systems may be mounted in the true, root file system.
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The approach selected by NuttX is intended to support greater
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scalability from the very tiny platform to the moderate platform.
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