AFS

AFS, which stands for Andrew File System, is a distributed file system developed by Carnegie Mellon University and later, a software product of Transarc Corporation, IBM, and OpenAFS. AFS distributes, stores, and joins files on networked computers. This distributed file system software makes it possible for users to access information located on any computer in a network. AFS focuses on security and scalability, or growing for more users. AFS can support thousands upon thousands of users all while maintaining a high level of performance and functionality. AFS uses several measures to achieve both security and scalability.

Security

On the security front, AFS uses two main methods. First, all users are authenticated using something known as Kerberos. Kerberos uses a combination of time stamps and keys to communicate between the user and the server(s) to establish identity. This allows a user to be "authorized" to use the system. Secondly, AFS uses an access control list which is a list that specifies what access privileges users have to a directory, specifically, the right to lookup, insert, delete, read, write, lock, or administer files in a directory (abbreviated as l, i, d, r, w, k, a, respectively).

Volumes

To aid in scalability, AFS employs something known as a volume. A volume is a container that keeps a set of related files and directories together on a disk partition for example a user's home directory. This provides for the user only having to know what volume their files are in as opposed to the physical location (server, driver, folder, etc). This allows administrators to move volumes, add more volumes, storage space, etc. all without having to worry that the user may loose track of where their files are located.