The role of architecture in the development of software systems

Systems increasingly rely on software as the main technology for implementing the desired behaviour. There is a clear trend of steadily growing sophistication in the behaviour of these systems. The availability of cheap and fast hardware suggests that successive generations of systems should exhibit greatly enhanced behaviour, but this increase in functionality is not observed to an extent that can be related to the progress made in hardware. To the contrary, systems grow in complexity very rapidly (as exemplified by their cost and the required sophistication of the development process), without providing much in terms of added functionality. This complexity, and resulting cost, limits the achievable level of sophistication in systems, unless techniques are found that allow the software complexity to be reduced very significantly. The imbalance between cost and functionality is discussed and arguments are presented suggesting it to be avoidable through a sound software architecture.