HP-UX System Administrator's Guide: Overview

Figure 3-1 Directory Tree Example
share vuelibbinadm
man9.Zman7.Z
man5.Zman4.Zman3.Zman2.Z
man1M.Z
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Key HP-UX Directories
This section describes many of the key directories in the HP-UX directory structure
and what they are used for.
/dev
Contains device special files. Though they appear in the
directory tree like regular disk files, device special files are
associated with physical devices or pseudodevices. They
are portals to the devices and device drivers they are
associated with.
Device special files are written to or read from by software
applications or operating system components to access data
on the devices, get status of the devices, or to control those
devices in some other way.
There are two classes of device special files (based on how
they are used to transfer data):
• block special files (transfer data in blocks by means of
the system’s normal buffering mechanism, and are
primarily used to mount file systems)
• character special files (transfer data in an unbuffered
stream, and are used for nearly everything else)
In HP-UX 11i version 3 there are also three types of device
special files (based on how they refer to their associated
devices):
• legacy device special files reference their corresponding
devices by the hardware paths to those devices. Legacy
device special files are the type of device special files
that have always been part of HP-UX. They are still
The HP-UX Directory Structure 45