Dept of Computer Science

Technical Staff

How are my files set up?

Last updated: July 31st, 2013 04:42 PM

The Computer Science Department uses the Andrew File System (AFS) to manage user accounts. This distributed file system allows user accounts to be accessed from any department machine as well as any other machine located throughout the world provided that machine is running AFS. A user does not need an account on remote sites to access AFS volumes and the files that they contain provided the appropriate AFS access rights are granted for these directories. If a user does have an account at another AFS site such as the University's CSSD department, these files may be accessed from this department's machines without having to log into University machines (see How do I access other AFS cells? below).

When you log into a UNIX machine, your current working directory is set to your home directory. Your home directory and all files and subdirectories are stored in what is called an AFS volume (or simply volume) which can be displayed by the AFS command "fs lq".

A user's home directory is initially set up with two subdirectories called "public", and "private", and a symbolic link to a backup directory called "Backup". The AFS access rights for each of these files is appropriately set and should not be changed. The public directory is world readable and is intended for sharing files with others and holding the user's World Wide Web home pages. The private directory is intended for personal files that a user wishes to protect from world-wide and local users.

A user's home directory can usually be referenced in UNIX shell commands by the syntax "${HOME}" or "~", the tilde character; the former syntax is the preferred method when referencing the home directory from shell scripts.

Access to particular files within a user's home directory is controlled by AFS access rights. The usual UNIX mode settings controlled via the UNIX command "chmod" are meaningless when the file or directory is located within an AFS volume.