A Modern Real-Time Software Design Tool: Applying Lessons from Leo

The special CCEJ issue on REAL TIME presented many new initiatives that are currently being developed. This short article introduces a software design tool that is currently being used on a variety of real time projects and which is based on principles similar to those employed 50 years ago on the LEO computer system. The Leo programming process was very effective in producing reliable software. A modern version of this, called StateWORKS, is based on abstract, finite state-machine models. In contrast to top-level modelling tools such as UML, which leave some coding to be done in the final stages, StateWORKS is an efficient method of implementing the final software and of avoiding much of the coding process. 1. Bread-boarding. 50 years ago, many designs were "bread-boarded " (built on a large, flat and very accessible panel on the bench) and the engineer would fiddle until his project seemed to function. This could take a long time, but the worst aspect was that the end product might not function under some marginal conditions. Testing is not a good substitute for meticulous design