The leftmost element of any valid DCE name is a root prefix. The appearance and meaning of each is as follows:
/...
This is the global root. It signifies that the immediately following elements form the name of a global namespace entry. Usually, the entry's contents consist of binding information for a DCE cell (more specifically, for some CDS server in the cell), and the name of the global entry is the name of the cell.
/.:
This is the cell root. It is an alias for the global prefix plus the name of the local cell; that is, the cell in which the prefix is being used. It signifies that the immediately following elements taken together form the name of a cell namespace entry.
/:
This is the filespace root. It is an alias for the global prefix, the name of the local cell, and the DFS junction.
DCE also supports a junction into the security service namespace, but there is no alias for this junction.
A prefix by itself is a valid DCE name. For example, you can list the contents of the /.: directory to see the top-level entries in the CDS namespace, and you can use a file system command to list the contents of the /: directory to see the top-level entries in the filespace.