# Subsections of Early Computing Machines

# The Antikythera Mechanism - 2D

YouTube Video## Notes About This Selection

This video outlines how the Antikythera Mechanism was found and some of the research that has been done on the mechanism. Getting its name from the island by which it was found, the Antikythera Mechanism had been hidden in the ocean for over 20 centuries. This is a textbook example of how humans have been automating processes for thousands of years. This video offers an insightful juxtaposition of using modern computers to analyze ancient computers.

## Reference

Antikythera - Anticythère - Αντικύθηρα - 安提凯希拉. “The Antikythera Mechanism - 2D”. June 25, 2011. YouTube. Available: https://www.youtube.com/watch?v=UpLcnAIpVRA .

# Introduction

YouTube Video#### Resources

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Today we’re going to be learning about historical computing machines. Now, computers like we know today with your electronic laptops and cell phones and everything aren’t just electronic, but really anything that can compute a value, whether it be mechanical, electrical, or even biological. What we’re looking at here is a piece of what is considered one of the oldest computing machines that we know of the Antikythera mechanism. It was discovered in 1900 off the coast of a Greek island called Antikythera and really is puzzled scientists for quite some time. It was believed to have originated around 100 BCE, but little was known about its origin. But however, from the detailed gears and inscriptions on the piece itself, we can actually deduce what it is actually used for. As you learned in the video, the Antikythera mechanism was an early computer used to calculate the position of the sun, moon and planets in the sky, as well as important dates and eclipses. Now, after this period of time, it wasn’t until the 14th century that mechanisms of this complexity were ever seen again, though this was completely beyond its time in terms of technology.

The Abacus is another early example of a competing machine that you’ve probably seen and heard of, or maybe even used. They’re now used a lot as a children’s toy. But this is an example of a Chinese Abacus. With a little bit of technique and training, this device allows the user to perform addition, subtraction, multiplication, division, and even the calculation of squares and cube roots at pretty high speed once you get used to it. But even with that, this machine still has a still has some room for human error, which is really what the the crutch of a lot of these devices are.

But moving forward a few hundred years, in the early 1600s, the slide rule was invented. It uses a sliding set of logarithmic scales, and allows the user to calculate all sorts of values from simple multiplication to logarithms and even trig functions. And for students studying engineering through the 1960s it was the tool of choice for those calculations needed until the calculator or the electronic calculator started to catch on and become small enough and useful enough for it to pretty much overtake everything else that we have used so far. Even though the slide rule is this simple device, it was used for even things like the Apollo 13 launch and if you’ve ever watched Apollo 13 before you can kind of see through this particular clip of the slide rule being used to verify some calculations.

# What is a Computer? (Part 1)

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Now that we have an understanding of the resources available at the time, let’s take a step back and think about what it would be like to be an inventor in let’s say the 1600s for a minute. If you wanted to design a machine that would aid in the computation of complex values, what should it do? What does that mean for a computer? Right? If we’re trying to avoid a lot of the human error that we have in calculating specific values, or make our lives easier, what should that computer what should that device actually do?

Based off of that discussion, or based off of that thought, I’m going to suggest four different things that a modern computer should be able to do. It should be able to compute some form of complex value and not just one calculation, but many, many types of calculations. It should be able to accept variable input. So not just a simple calculator that can accept numbers, but accept all sorts of different things like even a program, for example. It should be able to store information and should also be able to output that information as well. Because what’s the point of computing something if you can’t actually see what the result is? So you might see that many of these actually compared to the functions of computers today, right? The processor, a CPU that can compute value, programs for variable input, your RAM or your hard drive for storing information and your monitor or your printer that can output the results. Before we go further, right we need, we’ll need to figure out some way to compute values. And as we discussed earlier, human error is a major problem here. So regardless of how well the machine is capable of computing those values, we need to reduce or eliminate that factor of human error. So we want to design something that doesn’t have any humans involved in the calculation. Because if there is, like the abacus or the slide rule, the result is only as good as the person actually operating the machine.

So one step into that in 1642, Blaise Pascal invented the mechanical calculator to solve that problem. And now it was originally designed to help his father calculate tax revenues and of course if you know a little bit of history during that time period, taxes were pretty big deal and you know, if you collected too much from your townspeople, right, everyone grabbed their pitchforks and torches, and if you were the guy collecting taxes, if you didn’t collect enough, the king would go, you know, off with your head, that sort of thing, right? So this is a pretty big deal. Any sort of error could really literally mean life or death. So this machine was capable of addition and subtraction and could simulate multiplication and division by repetition. So, you know, essentially the beginnings of the calculator that we know and use today. Unlike the abacus, there’s much less room for human error. Here you input the numbers, and out come a result.

To further improve on Blaise Pascal’s design, in 1673 Gottfried Leibniz created a stepped drum, commonly referred to as a Leibniz wheel that greatly increased or enhanced the capabilities of any mechanical calculator that used it. With the innovations of these two guys here, the Pascal and Leibniz, the world now had the capability, at least the mechanical capability, to perform calculations.

That really led to Charles Babbage. And now in 1823, Charles Babbage designed his first Difference Engine, and built the prototype that was showcased in his study in his home for quite some time. Now, this is the, the larger version of that prototype, but the difference engine itself was capable of simple mathematics and could solve even polynomial equations up to six digits. So, this was a huge step forward, but it was only a small part of what Babbage had actually envisioned. The Difference Engine is what we call a fixed program or a single purpose computer, meaning that it could only do the task that it was built for; it couldn’t be reprogrammed to do anything else like our modern computers could. The Difference Engine could calculate the value of any seventh order polynomial, given the correct input by using method of finite differences. While the differentiation itself in its entirety wasn’t built during his lifetime, Babbage’s idea here was really truly revolutionary.

# Charles Babbage and His Difference Engine #2

YouTube Video## Notes About This Selection

While the creation on Babbage’s Difference Engine #2 was turned down by the government, we get to see this machine which was built in modern times. Babbage had a small prototype which he would demonstrate for party guests and it was clear to those who saw it, that Babbage was incredibly talented and intelligent. This is further proven by the prototype’s modern counterpart. It is astonishing that it was created with such precision using just pencils and paper!

## Reference

Computer History Museum. “Charles Babbage and His Difference Engine #2”. May 5, 2008. YouTube. Available: https://www.youtube.com/watch?v=KBuJqUfO4-w .

# How an 1803 Jacquard Loom Led to Computer Technology

YouTube Video## Notes About This Selection

In this video, we get to see another example of antique computers! Created in 1803, the Jacquard loom used technology that would be a predecessor to the more modern punch cards and in turn, modern computers. As before with the difference engine and the Antikythera mechanism, this was a result of humans trying to automate tasks which required a lot of precision.

## Reference

The Henry Ford. “How an 1803 Jacquard Loom Led to Computer Technology”. July 27, 2018. YouTube. https://www.youtube.com/watch?v=MQzpLLhN0fY .

# What is a Computer? (Part 2)

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So now that we have the capability of computing values without human error, once we have that ability, the next important part of the computer is to accept variable input from the user. And as I mentioned before, it’s not just the fact that we can input numbers into the computer. But, what if we could actually reprogram the device? Right? What if we could enable certain features or certain abilities of that computer by just pushing the input?

Can anyone guess what mechanical device was the first one to accept variable input from a user? It was the Jacquard loom. Not a whole lot of people know about the Jacquard loom, but it was invented in 1801 by Joseph Marie Jacquard, who basically simplified the process of manufacturing textiles. Particularly with textiles that have really complex or shifting patterns or even rounded designs and things of that nature. The Jacquard loom used a series of punch cards to control the thread. While this doesn’t actually perform any calculations, it is very important as this is the first example of a machine responding to different input or programs in the form of punch cards. Now, the car loom wasn’t the first thing that ever used the idea of punch cards. There was a few things before its time, but there’s Jacquard loom was one of the first one that truly automated the process. Although there were still some manual aspects of the Jacquard loom, the majority of it was completely automated.

The Difference Engine wasn’t the only computer designed by Babbage. The Analytical Engine, which was Babbage’s true dream: a general purpose computer. Had it been built as Babbage envisioned, it would have been one of the first true modern computers. He previously worked on design of an analytical engine, which was a true multi purpose computer. It would have been composed of several different parts that each performed different functions, allowing it to do many different kinds of calculations, be reprogrammed, store information and all sorts of different things. This was one of the first steps that we have seen, be developing or to developing a true modern multi purpose computer. Analytical Engine used a set of input cards called punch cards to determine what calculations to do and what numbers to use. And so this was greatly inspired by the Jacquard loom. This is very similar to how programs on today’s computers are structured: with a list of instructions on the program or in the program and the data that’s provided by the user.

Borrowing that idea from the Jacquard loom, the analytical engine was able to use a system of punch cards to accept input and determine the calculations that needed to be done. Babbage’s son remarked once that the Analytical Engine could calculate almost anything, it is only a question of the cards and time. So how many cards it would require and the amount of time it would take to actually operate, speculating that 20,000 cards would not be out of the question. It was a pretty impressive physical mechanical machine. This is very much like how modern computers worked, and even in the 40s and 50s a lot of computers worked off of this punch card system.

In the Analytical Engine, there is also the mill. The mill is really the heart of the machine. I was equate this closer to what a modern CPU was. In order to handle the computation done by the machine, Babbage designed this part that was capable of performing all of the basic numerical calculations. This used many of the breakthroughs that Pascal and Leibniz had some 200 years earlier. And so here in this picture on the slide is a very small picture of one part of the mill, which was constructed actually by Babbage’s son in 1910 to show that it was actually possible. The mill is able to perform all the basic arithmetic operations like addition, subtraction, multiplication, division, as well as calculate the square roots of numbers. This is really the first true step towards a modern CPU, which is really exciting. With those two parts in place, the next big hurdle was the ability to store data and output the results.

The store was Babbage’s true innovation. The store, which would have been a bank of columns capable of storing up to 1000 numbers up to 40 decimal places each. So that’s pretty high precision for a mechanical device. This was equated to roughly 16 to 17 kilobytes of modern day storage if you want to look at it that way, so quite a bit. Now, while the store was never actually built for the Analytical Engine, much of the design for the store was incorporated into his Difference Engine number two design, which is shown here in this picture. This represents the first time that calculated values could be stored directly in the machine, and recalled at a later time as required by the program.

The last thing that our computer should be able to do is output results. Charles Babbage also thought of this, right. As we saw in the video, in our previous lecture, Babbage also designed a printer that would output the results of calculations, not only onto paper, but directly into a plaster panel that could be used to create printing plates. You can imagine using this device to maybe make all of those tables in the back of your mathematic textbook. Which were a pain to do by hand, but now we could have a machine that would actually do the math and print it as well.

Now what those parts in place the stage is really now set for the coming computer revolution. Unfortunately, it will take an entire world consumed by war before the next major step in the history of computing was made. And we’ll pick that story up in the next couple of lectures.

This really leads us back to Charles Babbage, the father the modern day computer, it’s really quite mind boggling to see the Difference Engine, Analytical Engine, the Difference Engine number two, really all of which you only completed a simple prototype during his lifetime. And the fact that he was able to create these devices completely theoretically on paper, and they worked as intended exactly how he designed them is really, really quite amazing. Charles Babbage is known as the father of modern day computer because of these devices that were really truly one of the first examples of a general purpose computer. But if you’re interested in learning more about Charles Babbage, you can read his autobiography titled, “The Passages from the Life of a Philosopher” which is free and available online.

# Early Computing: Crash Course Computer Science

YouTube Video## Notes About This Selection

This video gives a great insight into what we will cover in this course. Our journey will start with early computation tools, such as the abacus, slide rules, and astrolabe! We see punch cards as a connection between early computing and modern computing.

## Reference

CrashCourse. “Early Computing: Crash Course Computer Science”. Feb, 22, 2017. YouTube. Available: https://www.youtube.com/watch?v=O5nskjZ_GoI