Down-time announcement and recovery network

The PLATO IV computer-based education system is a large scale timesharing communications network capable of supporting hundreds of remote terminals. Terminals are located in offices, college campuses and high schools throughout Florida and tie into the FSU computing system by standard voice grade phone lines.Anyone who has worked with computers is aware that occasionally an interruption of service will occur. It is especially important in the PLATO environment that all users be informed if the system must be down for a short unscheduled interruption.Since all the terminals are connected via dedicated phone lines, ideally, what is needed is a way to send downtime information through the phone network without having to rely on the computer or any of its associated peripherals. The DARN (Downtime Announcement and Recovery Network) which is currently under development at FSU will provide that capability.A standard cassette recorder will play pre-recorded streams of digital data words into the communications network. The cassettes are recorded with an interactive display and character designing editor while the computer is running, and a tape recording is then made of the formatted output. Thereby, even when the computer is down, this tape can be played back in order to recreate any display which was created at an earlier session with the computer. This paper will contain a description of the hardware and software utilized in making the DARN system work.