Stands for "Distributed File System." A DFS manages files and folders across multiple computers. It serves the same purpose as a traditional file system, but is designed to provide file storage and controlled access to files over local and wide area networks.
Even when files are stored on multiple computers, DFS can organize and display the files as if they are stored on one computer. This provides a simplified interface for clients who are given access to the files. Users can also share files by copying them to a directory in the DFS and can update files by editing existing documents. Most distributed file systems provide concurrency control or file locking, which prevents multiple people from editing the same file at the same time.
There are several types of DFSes, though some of the most common implementations include Server Message Block (SMB), Apple Filing Protocol (AFP), and Microsoft's Distributed File System (often called "MS-DFS" or simply "DFS"). DFS is included as a standard component of Windows Server, while SMB is typically installed on Linux machines.