Introduction

Abstract

“Computers” have attracted general interest only rather recently although computing devices have been known for a long time. The Antikythera mechanism, supposedly used by ancient Greeks to determine the motions of the stars and planets [1], the astrolabes of the middle ages [2], and Pascal’s calculator [3], are only a few examples of early computional devices. However, the present usage of the term “computer” includes neither those relatively primitive (though certainly effective) aids for computation, nor later developments like the slide rule, the planimeter, or the desk calculator. What we mean nowadays by a computer is a machine which performs a computation automatically and without human intervention, once it is set up for a specific problem. If we want to emphasize this distinction, we speak of automatic computers as opposed to calculators or computing devices.