UNIX Filesystems: Evolution, Design, and Implementation

Pseudo Filesystems

When people think of filesystems, they tend to think of a file hierarchy of files and directories that are all stored on disk somewhere. However, there are a number of filesystem types that provide a host of useful information but which have no physical backing store (disk storage). The most well known pseudo filesystem is /proc, which is used by the ps command as well as various debuggers.

This chapter describes some of the more well known pseudo filesystem types and provides a basic implementation of the ps command using the Solaris /proc filesystem.