DFS client machines provide computational power, access to DFS files, and other general-purpose tools. In some configurations, a server machine can also act as a client machine.
Client machines use a modified kernel that maintains contact with the File Exporter and server processes running on server machines. This collection of kernel modifications on a client machine is known as the Cache Manager. The main duty of the Cache Manager is to translate file requests made by application programs on a client machine into Remote Procedure Calls (RPCs) to File Exporter processes on File Server machines.
When the Cache Manager receives requested data from a File Exporter, it caches the data (stores it on disk or in memory) before passing it to the application program that requested it. In addition, DFS ensures that the Cache Manager always has access to the most current copy of the data. If the central copy of the file containing the data changes, the Cache Manager retrieves the newer version of the file the next time data is requested from the file (or in the case of read-only data, within a configurable period of time). The user does not have to direct the Cache Manager to keep a current copy; the Cache Manager's actions are automatic and completely transparent to the user.