Computer is nothing but a calculating machine. So it can be argued that it is just a calculator on steroids. The first calculator or adding machine to be produced in any quantity and actually used was designed and built by the French mathematician and philosopher Blaise Pascal. It could only do addition and subtraction, with numbers being entered by manipulating its dials.

In 1671 the German mathematician-philosopher Gottfried Leibniz designed a calculating machine which expanded on Pascal’s ideas and did multiplication by repeated addition and shifting. Leibniz was a strong advocate of the binary number system. Binary numbers are ideal for machines because they require only two digits, which can easily be represented by the on and off states of a switch.

Englishman, Charles Babbage, invented in the 1830’s a “Difference Engine” made out of brass and pewter (metal alloy) rods and gears, and also designed a further device which he called an “Analytical Engine”. His design contained the five key characteristics of modern computers:-

- An input device
- Storage for numbers waiting to be processed
- A processor or number calculator
- A unit to control the task and the sequence of its calculations
- An output device

Ada Lovelace was an associate of Babbage. She has become known as the first computer programmer.

Let’s jump few years and skip the great Alan Turing now who was an English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. Turing was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general-purpose computer. The “Nobel prize in Computing” – Turing Award is named after him 🙂 We’ll cover Turing in great detail some other day.

Inspired by Babbage’s analytical engine, IBM and Dr. Aiken of Harvard designed Harvard Mark 1. It was made of switches, relays, rotating shafts, and clutches. It was 8 feet high and 55 feet long. It was the first operating machine that could execute long computations automatically. It weighed ~4284 Kilograms. Successor of Mark 1 was Mark 3 which used mostly electronic components such as vacuum tubes and crystal diodes—but also included mechanical components such as rotating magnetic drums for storage.

This was very very short history of computers. We continue with one of the most important innovations in the technology: transistor.