Personal Perspective in History of Computing
As we all know that first tool using the computation was the abacus. During Middle Ages, some of the European philosophers made a several attempts to create a prototype analog computer and this was influenced by the Arabs and scholars that time. Yes "Arabs" know why? because they devoted their lives building and designing logical machines. but when John Napier discover the computation purposes and then many scientist followed in making a calculation tools like calculator or maybe an advance technology. the analytically engine posses many properties on electronic computers.
So this computers devices like abacus and other analog computers is now rare in our generation. and it takes consideration on more mathematical advancement in math or in theory before the first modern computers could be invented.