File Hierarchy Standard (FHS)
Stable: 15.06.2022 - 16:05 / Revision: 01.04.2022 - 16:33Template:ArticleMainWriter Template:ReviewersList Template:ArticleApprovedVersion
SUMMARY
This article lists and describes the OpenSTLinux file-system hierarchy (Weston and core).
1 Introduction
Linux® is a file-oriented operating system. This means that any application, library, or other information related, for example, to configurations and running applications is stored in files only.
The Filesystem Hierarchy Standard (FHS) defines the directory structure and directory contents in Linux distributions.
It is maintained by the Linux Foundation. The latest version is 3.0, released on June 3rd 2015[1]
The main parts described by the FHS are:
- the physical filesystem: any mass storage devices (NAND/eMMC/... partitions, USB key partitions, and so on)
- pseudo filesystem: created dynamically at boot-up (and/or at runtime) to store various information and configurations related to the software being run
- remote filesystem: rootfs can contain links to a network filesystem
OpenSTLinux images respect the latest FHS definition: 3.0
2 Root filesystem content
- The filesystem root of any Linux Distribution (OpenSTLinux included) is named '/' or 'root' (do not confuse with the 'root' super user name).
There are no files in the root path, only directories that shape the Linux FHS, as listed below:
| bin/ | Essential command binaries |
| boot/ | Static boot loader files |
| dev/ | Device files (temporary filessytem devtmpfs) |
| etc/ | Host-specific system configuration |
| lib/ | Essential shared libraries and kernel modules |
| media/ | Mount point for removable media |
| mnt/ | Mount point for temporarily mounting a filesystem |
| proc/ | Kernel and process information (pseudo filesystem procfs) |
| opt/ | Add-on application software packages |
| run/ | Data relevant to running processes |
| sbin/ | Essential system binaries |
| sys/ | Kernel and system information (pseudo filesystem sysfs)) |
| srv/ | Data for system-provided services |
| tmp/ | Temporary files |
| usr/ | Secondary filesystem-hierarchy |
| var/ | Variable data |
- As a standard Linux distribution, the OpenSTLinux distribution includes the optional user directories:
| /home | User home directories (optional) |
| /root | Home directory for the root user (optional) |
Details of the directory purpose, content or sub-hierarchy can be found in the official documentation: FHS-3.0
- OpenSTLinux also integrates a vendorfs filesystem, mounted on a dedicated Flash-memory partition (that is, /dev/mmcblk0p5):
| /vendor | Vendor dedicated directory |
This directory allows the storage of specific vendor libraries.