Building the Modern Computer: Babbage’s Analytical Engine
A couple of weeks ago, I wrote on the first automatic calculating machine, Charles Babbage’s Difference Engine. Although never completed until 2002, the Difference Engine was powerful. However, if we were to compare it to a modern machine, the Difference Engine was only a simple calculator (“Analytical Engine: Computer.”). Today, calculators are sold in dollar stores and even the expensive ones struggle to compare to a smartphone or laptop computer. Charles Babbage had to conquer the next big-thing, the world’s first general-purpose computer.
The Difference Engine project had failed in 1833, but by 1834, Charles Babbage was on to his next invention, the Analytical Engine (“The Engines.”).
Many today like to hold the Analytical Engine as the world’s first computer, however, a sharp reader of my pieces knows that it is not completely accurate.
I consider the Antikythera Mechanism, as the world’s first computer (at least discovered to date), but this difference of semantics in no way demeans the importance of the Analytical Engine.
As mentioned in a previous piece on the Difference Engine, Charles Babbage was not one to back down from a challenge.
So, when the Difference Engine project failed, Babbage dreamed up an even more powerful, complex, and ambitious engine.
The Analytical Engine was to be fully autonomous from start to finish, be constructed from over 12,000 individual mechanical pieces, weigh over 15 tons, and be approximately the size of a small steam locomotive (“Babbage Analytical Engine…”). Speaking of steam, the machine was to be powered by a steam engine eliminating the human operator from turning a crank.
What is more amazing about the Analytical Engine is its similarity to a modern computer. Without diving too far into the complexity of modern technology (smartphones, smart devices, laptops, and desktops included), computers require four major elements: a method of input (a touchscreen, mouse, keyboard, etc.), a method of output (the screen, a printer, etc.), a central processing unit (CPU), and a source of memory (in a modern computer this is RAM, random access memory) (“Analytical Engine.”). The Analytical Engine had all four of these major elements.
Babbage borrowed punch cards from the Jacquard Loom (discussed a few weeks ago) to develop a method of input based on the punch card system used for the Loom.
In fact, the Analytical Engine used four different types of cards to enter instructions, essentially an early computer program.
- Number cards entered the exact numbers to be computed in the calculation.
- Variable cards determined where the numbers should be stored, this is similar to the number’s address.
- Operation cards specified which operations would be performed; multiplication, division, etc.
- Combinatorial cards controlled how the variable and operation cards moved. For example, a combinatorial card could repeat 2 + 2, by simply reversing the two cards that added 2 + 2 (the number cards and operation cards) (“Analytical Engine.”).
All four of the cards used by the Analytical Engine are operations and processes still used by modern computers, albeit much more quickly and completely invisible to the computer’s user.
Similar to the Difference Engine, the method of output for the Analytical Engine was a small printing press. The result would be stamped using ink on a small roll of paper and pressed into a clay-like material from which to mold lead type plates for repeated use in a printing press (“Analytical Engine.”).
Just like your computer, the Analytical Engine had a CPU, a central processing unit (made by Intel or AMD today), although Babbage called it the mill (“Analytical Engine.). Here, a series of barrels, gears, and columns pulled numbers from the memory and stored them in smaller units of memory called registers (just like CPUs today). The mill would then perform the mathematical operation as directed by the punch cards. Once the calculation was completed, the result was stored in a register for use in another calculation, stored in the memory, or sent to the method of output to show the human user.
Today, computers use RAM, or random access memory, for short term memory. Babbage’s Analytical Engine used the store for its short term memory (“The Engines.”). Here over 1,000 numbers with up to 50 digits could be stored and used by the mill for calculation (“Analytical Engine: Computer.”).
The Analytical Engine is an extraordinary piece of mechanical design. Given its remarkable similarities to our own computers, it would be curious to compare it to a modern computer and the BBC did just that in 2011. The memory of the Analytical Engine, the store, (or RAM today) was able to store around 675 bytes of data (“Babbage Analytical Engine…”).
The average smartphone today can store around 4,000,000,000 bytes of data.
Computers also measure their speeds by clock cycles per second, measured in Hertz. The Analytical Engine could run at about 7 Hertz, which given its mechanical construction was very fast (“Babbage Analytical Engine…”).
However, modern smartphones run at around 2,100,000,000 Hertz.
Today, our computers store so much and run so fast, we use megahertz (MHz) or gigahertz (GHz) and gigabytes (GB) to measure their speeds and storage.
Unfortunately, given the failure of the Difference Engine project, the British Government wasn’t thrilled to fund another of Babbage’s dreams. Therefore, the Analytical Engine was never constructed. When Babbage died in 1871, it only existed in drawings, plans, and a few small demonstration models.
However, like the Difference Engine project, computer scientists, mathematicians, and engineers from around the world wondered if the device would actually function, if it were actually built. In 2011, a team of researchers, along with help from the Science Museum of London, began to digitize Babbage’s over 5,000 detailed drawings and share them worldwide (“Babbage Analytical Engine…”). They planned to develop a computer simulation of the computer and then build a working design to be completed by 2021, in time for the 150th anniversary of Charles Babbage’s death (“Babbage Analytical Engine…”).
I found little on the current state of the project, however, Plan28.org, the website used for the project seems to indicate that the project has been delayed (plan28.org). Nothing appears to have been built for the Analytical Engine as of this writing in June 2020. This will certainly be an exciting project to watch. The Analytical Engine directly inspired, influenced, and gave us our modern computers. If you’d like to keep your eye on the project, visit https://plan28.org/.
The Analytical Engine was built upon previous technologies, most notably the Jacquard Loom and the Difference Engine.
As we will discuss (make sure to follow me on Medium and subscribe on YouTube), future technologies will be built on the developments presented in the Analytical Engine. Remember, before we could drive around in cars, someone had to invent the wheel. We should never criticize previous generations for their lack of technology and what we view as innovation. Without the seemingly primitive inventions they created, we would be much further from our modern computers.
The Analytical Engine is the fifteenth major milestone in the history of computing.
More on Previous Technologies:
More on the History of Computers:
Works Cited
“Analytical Engine.” Analytical Engine — History of Charles Babbage Analytical Engine, history-computer.com/Babbage/AnalyticalEngine.html.
“Babbage Analytical Engine Designs to Be Digitised.” BBC News, BBC, 21 Sept. 2011, www.bbc.com/news/technology-15001514.
“The Engines.” The Engines | Babbage Engine | Computer History Museum, www.computerhistory.org/babbage/engines/.
Harris, William. “Who Invented the Computer?” HowStuffWorks Science, HowStuffWorks, 30 Jan. 2020, science.howstuffworks.com/innovation/inventions/who-invented-the-computer1.htm.
Markoff, John. “It Started Digital Wheels Turning.” The New York Times, The New York Times, 7 Nov. 2011, www.nytimes.com/2011/11/08/science/computer-experts-building-1830s-babbage-analytical-engine.html.
“Plan 28: Builder Charles Babbage’s Analytical Engine.” Plan 28: Building Charles Babbage’s Analytical Engine, plan28.org/.
Swaine, Michael R., and Paul A. Freiberger. “Analytical Engine: Computer.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 26 May 2020, www.britannica.com/technology/Analytical-Engine.
