Application programs then use the cached copy, which eliminates repeated network requests to file server machines. Cached File A copy of a file that the Cache Manager stores on a workstation's local disk. Callback A promise from the File Server to contact the Cache Manager if the centrally stored copy of the file changes while the Cache Manager has a cached copy. If the file is altered, the File Server breaks the callback. The next time an application program asks for data from the file, the Cache Manager notices the broken callback and retrieves an updated copy of the file from the File Server.
Callbacks ensure the user is working with the most recent copy of a file.
Cell An independently administered site running AFS, consisting of a collection of file server machines and client machines defined to belong to the cell. A machine can belong to only one cell at a time. Client Machines Computers that perform computations for users. Users normally work on a client machine, accessing files stored on a file server machine. Command A string of characters indicating an action for an AFS server to perform.