HP-UX file system structure is like an inverted tree with the root of the tree at the top and branches and leaves connected to it toward its bottom. The top level is root and represented by the forward slash (/) character. When you install HP-UX Operating Environment, seven file systems are created, by default. These are /, /stand, /var, /usr, /tmp, /opt and /home.
Some of these directories contain static data which refers to file contents that are usually not modified while some holds dynamic or variable data which refers to file contents that are modified when required.
The Root file system (/): The root file system contains many higher level directories which hold specific information. Some of the important directories under the root are:
The Binary directory (/bin): This directory contains user executable commands. It is linked to /usr/bin directory. /bin directory holds static data.
The device directory (/dev): This directory contains files for hardware devices. There are two types of device files ‘block special device files’ and ‘character special device files’ (Raw device files) some important sub-directories under /dev are: dsk, rdsk, rmt, pts and vg00. The /dev directory contains static data files.
The Library Directory (/lib): This directory contains shared library files which are required by programs. The /lib directory can also be accessed using /usr/lib directory since both are linked. The /lib directory contains static data.
The system Binary Directory (/sbin): The most commands required at system boot up and commands that require boot privileges to run are located in this directory. The /sbin directory contains static data.
The Etcetera directory (/etc): This directory holds most system configuration files. Some of the important sub-directories under /etc are rc.config.d, default,opt, dt,ftpd,lp, lvmconf,mail, sam, skel and vx. The /etc directory contains static data.
The lost+found directory (lost+found): This directory contains files that become orphan after system crash. Orphan file is that which has lost its name. This directory is automatically created when the file system is created.
The Net directory (/net): If autofs is used to mount NFS file systems using special map, all available NFS file systems on the network are mounted beneath /net directory.
The Kernel file system (/stand): The kernel files are located in /stand file system. Files that contain kernel code, boot device information, kernel parameters and module information are stored here. This directory is altered only when kernel update is required.
The Variable file System (/var): This directory contains frequently changing data while system is up and running. Files holding log, spool, status and other dynamic data. Some important sub directories under /var are /var/adm, /var/dt, /var/mail, /var/spool, /var/tmp, /var/opt
The UNIX System Resource file system (/usr): This directory contains general files related to system. Some important sub-directories under /usr are /usr/sbin, /usr/local, /usr/include, /usr/share, /usr/lib.
The Temporary file System (/tmp): This file system contains temporary files. Temporary files are created by programs when they run. These files get removed after system reboot.
The Home file system (/home): This file system is used to hold users home directories. Whenever a user account is created, it assigns home directory for that user to keep his personal files. No other user can access other user’s home directory.
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