No, no, no; that's not what AFS volume means. In order to
understand AFS, it is important to know some basic terminology.
Following is a list of terms to provide you with some important background
for when you use AFS:
- Volume: An AFS volume is a collection of files and
directories that are grouped together as one unit. A volume can
be backed up, renamed, moved from one server to another,
replicated, created, or destroyed as a unit.
- User: A user is someone who is registered with AFS. You
must be registered with AFS if you wish to be able to own
files. The process of telling AFS who are you is called authentication.
- Group: A group is a list of users. Currently, it is
not possible for a group to contain other groups.
- Cell: An AFS cell is essentially a domain
of authority. It is currently the largest unit used in AFS.
Each cell has a list of administrators, a list of users, a list
of groups, and a list of volumes. Each of these lists is private
to the cell. This means that an administrator in one cell may
or may not have any access to another cell. A user in one cell
may not even exist in another. A cell is also a domain of
authentication. If you are the user qjb in the athena.mit.edu cell, you may not have any access at all to
files belonging to a user named qjb in the andrew.cmu.edu cell. Likewise, someone who has
administrative capabilities in the sipb.mit.edu cell may
not be able to touch the athena.mit.edu cell.
- ACL: ACL stands for Access Control List. When
referring to access control lists, some people say the initials
(``A-C-L'') and others pronounce the acronym (``ackle''). An
access control list pairs users and groups with operations that
they are allowed (or not allowed) to perform. Although access
control lists are used for much more than just AFS, only AFS access control lists will be discussed here. A typical access
control list would say something like, ``The user potato
is allowed to create files in this directory. The user soup is allowed to modify existing files and create new files
in this directory. Anyone else is allowed only to read files in
this directory.'' AFS access control lists and how to use
them are explained in more detail later in this document.