The Origins of Computers: The Abacus and The Astrolabe

It seems logical when considering the origins of computers to begin with the first computer. We could start our story with Colossus, influenced by Alan Turing and Max Newman, and built by Tommy Flowers in 1943. It was used to crack German radio encryption during the war and is generally regarded as the first digital computer. But is this a good place to start? And does it help us understand the origins of computers?

The answer sadly is no, for many reasons. To begin, Turing and Flowers weren’t the first people to consider the idea of a computer. And Colossus itself isn’t regarded as a general-purpose computer, or in technical terms Turing Complete.

Also, around the same time as Colossus, there were many other advanced calculating and computing tools. The Germans built the Z1, Z2 and Z3 between 1936 and 1941, along with their encryption tools. In 1938 the Polish built a Bomba to crack German encryption. This inspired Turing’s Bombe machine a few years later, which cracked Enigma. And the Americans built ABC in 1942 and then the more famous ENIAC in 1945. So Colossus didn’t occur in isolation and its difficult to classify it as the first computer.

The ideas which developed in the war period weren’t original either. We know over 100 years earlier Babbage and Lovelace had advanced ideas on computers. Babbage produced many detailed designs and even a prototype mechanical computer. What he called his Difference Engine and Analytical Engine.

As touched on in my post on the Origins of Mathematics, ideas tend to emerge slowly from the fog of history. So we can’t be sure when ideas first appear. The computer is no different, particularly as it is just the implementation of an idea. An idea that has been developing over centuries and millennia.

Evidence for mathematics goes back about 6,000 years. By contrast, the evidence for computing tools goes back less than half this time. This doesn’t mean people were not using computing tools earlier, it just means we lack explicit evidence. Also, the evidence we do have should not be classified as first of its kind, it’s very unlikely that is the case either.

In terms of our definition, ‘computing tool’ simply means a tool that helped someone count, calculate, or compute something. Many like to use the term analogue computer, but this may be a little advanced for some of our purposes. Ultimately we’re looking for the tools people developed to achieve a behavioural goal, like computing the date of a religious event or conducting trade.

The first of these tools is the abacus, a tool that is still used to count and calculate. The original abacus was known as a counting board and wasn’t like the abacus we know today and children play with. They were made of wood or stone, they had grooves cut into them, and small stones or discs were placed in the groves and used to count. Some were even just small boxes of sand with lines drawn into them with a stylus.

The oldest example of a counting board is the Salamis Tablet. Made of marble, it was discovered on the Greek island of Salamis and dates back to around 300 BC. The Chinese were also known to be using the abacus around the 2nd century BC, and there is some evidence of much earlier use.

The abacus is important because it is one of the first examples of humans developing a calculation tool to help with everyday life. It was mainly used by merchants but it is a tool most people will have interacted with at a market or in a shop. The abacus also begins a long lineage of calculations tools.

Abaci evolved into electro-mechanical calculators, pocket slide-rules, electronic calculators and now abstract representations of calculators or simulations on smartphones.

Another interesting and more advanced tool is the astrolabe. It was made up of overlayed disks and rings, often of wood or metal. These disks and rings contained different astronomical information, such as important stars.

An astrolabe from the Mamluk Sultanate dated 1282. The astrolabe was used to calculate time, location and direction. It was also used widely in astrology to predict important religious events. And in the Islamic world it was used to calculate the direction of Mecca. It’s not precisely clear when the astrolabe first appeared, but evidence suggests some time between 200 BC and 500 AD.

The most interesting feature of the astrolabe is it was programmable. Each astrolabe came with a number of disks. These disks imputed different base information into the system dependent on the user’s latitude. The disks were usually associated with the night skies of the major cities of the period. This enabled the user to make calculations no matter where they were.

The astrolabe was significant, as Smithsonian Magazine described it.

“Imagine a device that can do everything: Give you the time, your location, your horoscope, and even help you make decisions—all with the swipe of a hand. It’s overpriced, customizable and comes with a variety of bells and whistles. No, this isn’t the iPhone 7. It’s the astrolabe.”

The final tool of interest, and the most advanced, is the Antikythera Mechanism. It is an orrery which is a mechanical model of the solar system. It could be used to predict the position of celestial bodies and eclipses years into the future. It is described as the first example of an analogue computer.

The mechanism was discovered in a Roman shipwreck in 1901, off the coast of the Greek island of Antikythera by sponge divers. The device can be dated to somewhere between the 1st and 3rd century BC. It is incredibly advanced for the period and suggests human thought on computers had progressed significantly, as Professor Kyriakos Efstathiou says.

“All of our research has shown that our ancestors used their deep knowledge of astronomy and technology to construct such mechanisms, and based only on this conclusion, the history of technology should be re-written because it sets its start many centuries back.”

The overall point here is not to suggest the abacus, astrolabe or the Antikythera Mechanism represent the first computer in the way we understand computers today. It is to highlight how humanity had begun to think about computers, or at least tools to calculate and compute, a very long time ago.

As with mathematics there is no origin point for the computer, and we will never find one. But the tools mentioned do show over 2,000 years ago humans had already taken their first steps towards the computer. And this is an important point for modern computer scientists and software developers to grasp. Many great minds have made enormous strides over the last 100 years and put computers in our pockets. But there were some equally great minds who did incredible work 2,000 years ago. We should remember we are not unique in our genius, and our achievements rest on small steps taken thousands of years ago.

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