In recent years, the application of digital computers to process control has been shown to have real advantages over the traditional analogue (electronic and pneumatic) techniques. However, there have often been severe practical difficulties which prevented the achievement of these advantages, and which have slowed down the acceptance of digital control, particularly for smaller systems. This paper briefly discusses the advantages, then examines the potential problems, of digital control. Then follows a description of a new system which is shown to provide most of the advantages of digital control, whilst avoiding the mysteries and difficulties which have been so common in the past. The author, Dr Romilly Bowden, was the prime operator in the early design, and in the subsequent development both in England and America, of the Diogenes project on which this article is based. The classical name for the process controller was coined, rather whimsically, at an impromptu technical conference somewhere over the eastern USA. The constant reference to diodes (as programming devices, mostly) evoked the response “It's positively diogenous!” (ie, full of diodes). From this it required very little to produce the name of the ancient Greek philosopher. Despite the high-flying etymology, in down-to-earth terms, systems are operating successfully in a variety of American process plants, and work is in hand for further systems in Europe.