Watch-Dog Communication Link

ForMAT and Prodigy/Analogy are linked in real time, either through an internet connection provided by USX or directly through ftp sharing of communication messages. The link can be viewed as a ``watch-dog,'' which supervises the communication between the two systems.

The watch-dog runs on both ends of the communication channel (i.e., one watch-dog process runs at CMU while another runs at BBN). The Watchdog queues all data files which are created by either process, and only makes data available when a process is ready for it. The Watchdog uses a "mailbox" facility to notify the user of the client when data is available from the server. For example, note that during the start-up screen on the CMU side, the watch-dog icon shows a ForMAT logo. When ForMAT passes a data file, the watch-dog sets this icon to a PRODIGY logo (see screen shot). By handling data synchronization and basic user notification, the Watchdog simplifies coding effort for both sides.


Last Edited: May 6, 1997