Software I: Function-level computing: A new programming method, linked to radically different architectures, may greatly simplify software development

Computer hardware has advanced tremendously in the last 25 years, going from vacuum tubes to very large-scale integrated circuits. In the same period neither the architecture of computers nor the programming languages used to control them have changed significantly. As a result, the expanding capabilities of VLSI are not being fully exploited and the costs of much-needed programs are soaring. Recognition of this fact has focused attention on a style of programming called functional programming, which offers the prospect of much cheaper programs and new machine architectures that exploit VLSI. The functional approach rejects the model of computing conceived by the mathematician John von Neumann and others. The von Neumann model is based on a computer consisting of a central processing unit (CPU), a store or memory, and a connection between them that transmits a single unit of data, or “word,” between the CPU and the store. Because today's programming languages are modeled on such computers, programs are complex, concerned with the smallest data entities, and seldom reusable in building new programs.