Book excerpt: This book is intended to provide an introduction to, and an overview of, the computer industry - or the "Computer Age" - as well as the key people who created the computerised world we live in... without too many technical details. The idea is to offer a snapshot of the industry at this point in time and find out how it got where it is today, highlighting its most notable inventions and innovations and the pioneering people who are responsible for them.Extract: The original human computers used tools to help them calculate. The most well known calculating tool from antiquity is the abacus, which was usually made from wood and featured a frame containing sticks along which beads could be moved. It is believed that the abacus was invented some time between 2700-2300 BC, in Sumeria, and its forerunner was probably a system whereby stones or beads were moved along grooves in the sand or ground, or tablets of wood, stone or metal.