Getting closer

25.02.2016 |

Yesterday, we learned all about mechanical computers. Today, we are moving a step ahead in historywe are going to learn about electro-mechanical computers, followed by programmable computers.

An electro-mechanical machine is one that either uses electrical power to create mechanical movement or mechanical movement to create electrical power.

The next character in our story is Herman Hollerith. He realized that the location of holes in punched cards could represent data, somewhat similar to rows and columns, and that these data could be counted or arranged. He built the Hollerith tabulating machine using this idea, and his machines were used for the 1890 census by the United States. Hollerith soon founded the Tabulating Machine Company, which eventually became IBM (International Business Machines) in the year 1924.


Image Source: Licensed under Creative Commons Attribution 2.0 Generic license

Hollerith Machine
Image Source:
Licensed under Creative Commons Attribution 2.0 Generic license


It was IBM that built the next milestone in the history of computers: the Harvard Mark I computer. Interestingly enough, this is the same computer that aided in building the atomic bomb used by the United States during the World War II in 1944.

Even before the Harvard Mark I, in 1941, the Z3 was completed by Konrad Zuse in Germany. The Z3 was an electro-mechanical computer based on two earlier computers built by Zuse: the Z1 and Z2.

Just after World War I, the Enigma machine was invented by German engineer Arthur Scherbius. These are the same machines that were used to code messages by the German army during World War II.

In order to decode these messages, Alan Turing designed the Bombe.

The computers that we have seen so far could perform only a certain type of task. If we built an arithmetic computer, we could not expect it to code or decode sentences, and vice-versa.

That is, until 1943, when Colossus computers were created. These machines are known as the world’s first “programmable computers.”

Programmable computers could perform more than one type of task, but the Colossus computers had to be programmed by plugs and switches instead of our usual concept of a computer program.

The electronic Manchester Baby computer was, in the truest sense, the world’s first programmable computer, because it had a stored program. The success of the Manchester Baby led to the building of the Manchester Mark I.

It was the Manchester Mark I that was bettered into the Ferranti Mark I computer, which was the world’s first commercially available programmable computerthat is, a computer in the truest sense.

Tomorrow, we begin exploring “real” computerscomputers that we can actually relate to.

Thanks, and have a great day!


Recommended book

“Alan Turing: The Enigma” by Andrew Hodges


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