In the
Berkeley Software Distribution
The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berk ...
(BSD) and its descendants, kernfs is a
pseudo file system
In computer science, a synthetic file system or a pseudo file system is a hierarchical interface to non-file objects that appear as if they were regular files in the tree of a disk-based or long-term-storage file system. These non-file objects m ...
that provides access to information on the currently running
kernel. The
file system
In computing, file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one larg ...
itself and its content are dynamically generated when the
operating system is
booted, and the kernfs is often
mounted at the directory.
As a result of its nature, kernfs does not consist of actual files on a
storage device, allowing instead
processes
A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic.
Things called a process include:
Business and management
*Business process, activities that produce a specific se ...
to retrieve system information by accessing
virtual files.
kernfs first appeared in
4.4BSD The History of the Berkeley Software Distribution begins in the 1970s.
1BSD (PDP-11)
The earliest distributions of Unix from Bell Labs in the 1970s included the source code to the operating system, allowing researchers at universities to modify a ...
,
and NetBSD 6.0 continues to use kernfs by default while mounting it at the canonical mount point.
See also
* procfs a special file system in Unix-like operating systems that presents information about processes and other system information
* tmpfs a common name for a temporary file storage facility on many Unix-like operating systems
References
Special-purpose file systems
Unix file system technology
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