
<P>
Messages are received much the way they are delivered. The transport driver receives a message, registers it with the Mailbox library, and passes its data, block by block, to the appropriate data driver. The data driver translates this message into its own data format. The Mailbox library stores the message in its <EM>
inbox</EM>
 until it can deliver the message. When the appropriate time for delivery is reached, the Mailbox library starts up an appropriate application (if it is not already running) a