DISCUSS uses a client/server model of networking. A client is a program run by you, the user, to read meetings and otherwise work with DISCUSS. DISCUSS servers actually store the information kept in the meetings, while the DISCUSS client programs handle the user interface. When a user runs a DISCUSS client program, it contacts the various servers to manipulate the meetings.
Three main DISCUSS client programs are available: terminal-oriented discuss for running in an xterm window or over dialup; edsc for running within emacs; and an X-based client, xdsc which opens a new window. The use of each of these clients is described in the following sections.
Because of the networked nature of this system, some sort of authentication scheme needs to be used. If such a scheme is not used, it becomes easy to generate fake electronic mail messages and enter them as transactions. In order to prevent fake transactions and to ensure privacy, the Kerberos system, developed on MIT's Project Athena, is being used to authenticate user transactions. Although Kerberos is not completely secure, it is the most secure system now available, even if it is not the simplest. If you are using an Athena workstation, there is nothing further you need to do to use Kerberos; you can start using DISCUSS immediately. If you are not on an Athena workstation, refer to Section 8.1 for more information about using Kerberos.