Back in the early '90s we were working on automating an aluminium smelter in Australia. We developed a system called Message Director: a publish and subscribe system that allowed applications to communicate on bus where messages were published, and subscriptions made to, a director application. All messages were logged and applications could be changed or added to without effecting other applications. It was incredibly successful. We finished the automation with a team of 3 people within time and under budget.

In a publish and subscribe system, senders and receivers of messages are ideally not associated. However, the problem with the original system was that because data was binary data a receiver of a message had to know the format of the messages it was receiving.

Subsequently I went on the develop the concept into a more universal system called Universal Message Manager (UMM). In UMM all messages are self-describing. Small apps (called agents) can be written that have a simple task: receive these messages, do a task and send those messages. In one example that comes with the project. we have a tank monitoring system. A tank monitoring agent sends messages on the tank level, a pump agent receives messages when the tank level is below 10% and above 90%, switches on and off accordingly, and sends out confirmations messages. These messages can be seen on the screen, logged and a database application logs them the a database.

UMM is ideal for teaching as the agents are self-contained but can be used together to form a complex system. Another example on our website is a parcel sorting machine. The agents in the project are written in Python with a C option available. Agents can be written in any language.

The UMM project and documentation can be downloaded from https://umm.braham.net. It is free for non-commercial use.

We're particularly interested in people who want to use UMM for teaching.