-we enter a new message in a room, we slide all the old message-numbers
-down a slot, and probably the oldest one falls off the bottom (in which case
-we must delete it from the message base). Reading a rooms is just a matter
-of looking up the messages one by one and sending them to the client for
-display, printing, or whatever.
+we enter a new message in a room, its message number is appended to the end
+of the list. If an old message is to be expired, we must delete it from the
+message base. Reading a room is just a matter of looking up the messages
+one by one and sending them to the client for display, printing, or whatever.