Which types of computers predated Babbage's “analytical engine”?
Computers developed from calculating machines. One of the earliest mechanical devices for calculating, which is still widely used today, is the abacus—a frame for carrying parallel rods on which beads or counters are strung. The abacus originated in Egypt in 2000 B.C.E. It reached the Orient about a thousand years later, and arrived in Europe in about the year 300 C.E. In 1617, the Scottish scholar John Napier invented “Napier’s Bones”—marked pieces of ivory for multiples of numbers. In the middle of the same century, the French mathematician Blaise Pascal produced a simple mechanism for adding and subtracting. Multiplication by repeated addition was a feature of the stepped drum or wheel machine of 1694, invented by the German mathematician Gottfried Wilhelm Leibniz.