<P> In a computer file system, and primarily used in the Unix and Unix - like operating systems, the root directory is the first or top-most directory in a hierarchy . It can be likened to the trunk of a tree, as the starting point where all branches originate from . The root file system is the file system contained on the same disk partition on which the root directory is located; it is the filesystem on top of which all other file systems are mounted as the system boots up . </P> <P> To use the example of a physical file cabinet, if the separate drawers in the file cabinet are represented as the highest level of sub-directories in the file system or system prompt, then the room the file cabinet is in may be represented as the root directory . That is, the other directories may be inside it, but the root directory cannot go in any other directories, at least in that file system . In most operating systems, files can be placed inside the root directory, as well as in its sub-directories . One may envision this as placing paper files anywhere in the room, or into any file cabinet within the room . </P> <P> Unix abstracts the nature of this tree hierarchy entirely and in Unix and Unix - like systems the root directory is denoted by the / (slash) sign . Though the root directory is conventionally referred to as /, the directory entry itself has no name--its name is the "empty" part before the initial directory separator character (/). All filesystem entries, including mounted filesystems are "branches" of this root . </P> <P> Under DOS, OS / 2, and Microsoft Windows, each partition has a drive letter assignment (labeled C:\ for a particular partition C) and there is no common root directory above that . DOS, OS / 2, and Windows do support more abstract hierarchies, with partitions mountable within a directory of another drive, though this is rarely seen . This has been possible in DOS through the command JOIN since it first was added to DOS, and can be achieved in all Windows versions as well . In some contexts, it is also possible to refer to a root directory containing all mounted drives, although it cannot contain files directly as it does not exist on any file system . For instance, when linking to a local file using the "file:" URI scheme, the syntax is of the form "file:///C:/...", where" file: / / "is the standard prefix, and the third' /' represents the root of the local system . </P>

Which directory off of root normally contains log files on an ubuntu server