Introduction to Zephyr

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 Battlestar Galactica to the next 6.01 problem set. The usage of Zephyr has far exceeded original expectations. Over time, people have also created programs that give Zephyr a graphical interface, and programs that give zephyr a purely textual interface, that can be used entirely within a ssh terminal. Some of these zephyr clients have become so widely used that there are users who do not know that there are other ways to send (and receive) zephyrgrams. This document will cover the traditional commands, typed at the athena% prompt, as well as the more common modern zephyr client BarnOwl. Other 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 windowgrams, containing text and information about the sender. If you are using a modern zephyr client, the zephyrgrams will appear in other ways. 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. However, it has become common for BarnOwl users to leave themselves permanently logged in, or ``permalogged'', by having a zephyr client that is always receiving messages, even when they are not logged-in to read them. Text-based zephyr clients, such as BarnOwl, and the UNIX utility screen(1) (that allows for programs to continue running when you log out, and be resumed (reattached) when you log in again), have made this usage possible.