Andrew File System

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What Does Andrew File System Mean?

Andrew File System (AFS) is a distributed network file system developed by Carnegie Mellon University. Enterprises use an AFS to facilitate stored server file access between AFS client machines located in different areas. AFS supports reliable servers for all network clients accessing transparent and homogeneous namespace file locations.


An AFS may be accessed from a distributed environment or location independent platform. A user accesses an AFS from a computer running any type of OS with Kerberos authentication and single namespace features. Users share files and applications after logging into machines that interact within the Distributed Computing Infrastructure (DCI).

Techopedia Explains Andrew File System

In distributed networks, an AFS relies on local cache to enhance performance and reduce workload. For example, a server responds to a workstation request and stores the data in the workstation’s local cache. When the workstation requests the same data, the local cache fulfills the request.

AFS networks employ server and client components, as follows:

  • A client may be any type of machine that generates requests for AFS server files stored on a network.
  • After a server responds and sends a requested file, the file is stored in the client machine’s local cache and presented to the client machine user.
  • When a user accesses the AFS, the client uses a callback mechanism to send all changes to the server. Frequently used files are stored for quick access in the client machine’s local cache.

AFS equips users with multiple access control permissions, as follows:

  • Look Up (1): Users may access and list AFS directory and subdirectory content and review a directory’s access control list (ACL).
  • Insert (i): Users may add new subdirectories or files.
  • Delete (d): Users may remove directory files.
  • Administer (a): Users may modify the home directory’s ACL.
  • Read (r): Users may view file directory or subcategory contents, as AFS supports the standard Unix Owner Read permission control set.
  • Write (w): Users may modify or write files, as AFS supports the Unix Owner Write permission control set.
  • Look (k): Processors may use the directory to execute programs requiring Flock files.

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.