# Charles Babbage

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#### Video Script

##### Charles Babbage (Slides 23-17)

Charles Babbage designed many different engines during his lifetime, but very few of them were actually built.

In the previous video, you saw a completed version of the Difference Engine built very recently, which we actually see here. And his Difference Engine was very revolutionary because it proved that you could build a device that was purely mechanical, that could perform calculations. But the difference engine was actually a very small part of Babbage’s overall vision for building these mechanical computational devices.

He also designed another engine that he called the Analytical Engine, and it was never completed during his lifetime and thus far it has not been completed in modern day time either, but there are small parts of it that exists. For example, this is one small part of it that is in a museum. The analytical engine would have been a true multi-purpose computer. Instead of just performing Newton’s method of divided differences, it was capable of performing all sorts of different mathematical operations.

Babbage’s Analytical Engine would have been programmed using input cards, such as what you see here. And one surviving portion of the Analytical Engine is the Mill, which is a general purpose computational device that can perform all sorts of different mathematical operations. It’s very similar to the CPU in modern computers.

In addition, he would have created a device called the store, which was capable of storing and retrieving up to 1000 numbers at 40 decimal places, which is roughly 16 kilobytes of data, which is really respective for the 1800s. And parts of the design for the store were actually used in the design of the Difference Engine, which is the picture you see here. So what have looked very similar.

And so because of all of his work, designing and thinking about how you would build these multipurpose computational devices, we refer to Charles Babbage as the father of modern computing. Unfortunately, a lot of his designs were forgotten over time. And it wasn’t until very recently that his work was really recognized as being so revolutionary in the history of computing science. In a later lecture in this class we will actually analyze some more work of Charles Babbage, specifically the Analytical Engine, and how it fits better into the history of computing science.