Zephyr was a system designed to let system administrators send important messages to users in an easily noticeable format. It was meant to have a low volume of traffic and be used only for official notices. This is obviously not what Zephyr is today. It is still used in the way it was intended: notice that you get official zephyrgrams as you log in, with important information about Athena services and planned outages. However, the most common usage is by average users exchanging information about classes, how their days are going, and talking on Zephyr classes and instances about everything from the latest episode of Babylon 5 to the next 6.001 problem set. The usage of Zephyr has far exceeded original expectations. Over time, people have also created programs that give Zephyr a graphical interface. Some have become so widely used that there are users who do not know that there are other ways to send (and receive) zephyrgrams. In this document all the commands given are to be typed at the athena% prompt in your xterm or terminal window. Programs, such as xzewd, will be mentioned later in this document. They are not Zephyr, but are graphical programs that execute Zephyr commands.
Zephyr allows you to communicate with other users in real time. Zephyr messages appear on your screen as windows, called zephyrgrams, containing text and information about the sender. Zephyrgrams can only be received when you are logged in and you can only send zephyrgrams to other users who are logged in and subscribed to messages.