ENIAC: Celebrating Penn Engineering History

History: Preceding Technologies

Computation devices themselves are as ancient as the human race, and their story has also been rehearsed all the way back to the earliest digital devices - the fingers - by way of piles of stones to "Napier's Bones," an analogue device invented by the father of logarithms. The abacus is still in use after 5,000 years, while the slide rule, invented in 1621, was only superseded by the modern computer. Read on to learn about the inventions which contributed to the development of ENIAC and eventually, the computers we use today.


Mechanical Brains - These allowed humans to calculate larger mathematical operations faster than could be done "in the head" alone. Examples of these are:

The Abacus: Decks of beads and rods used to calculate addition, subtraction, division and multiplication, along with being able to extract square and cube roots. Learn more.

The Slide Rule: Ruler-shaped device used to calculate multiplication and division, along with more advanced functions such as logarithms and trigonometry. Learn more.

The Difference Engine: Developed by Charles Babbage, this machine was an automatic calculator used to calculate polynomial functions. Learn more.

Mechanical Calculators: Various calculating machines, from desk-top size to hand-held, that allowed users to perform advanced mathematical functions. Learn more.

The Differential Analyser: At Penn Engineering, the Differential Analyser was in use and operated by secret human "computors," women during World War II who were employed at The Moore School doing ballistics calculations for the war effort. The Differential Analyser is considered by many to be ENIAC's closest relative. Learn more.

Vacuum Tubes - used to create switches by manipulating the flow of electrons. Common uses were found in early radio and television sets. The better the tubes became, the faster switches were able to be turned on and off. This led to a faster computer, because computers at the time relied on these switches. Learn more.

Punched Cards - this technology was in the form of paper cards that contained digital information by the punched out holes in predetermined patterns on the cards. These cards were used in such areas as fairgrounds (to operate the player-pianos and organs) to controlling the textile looms in industrial mills. Punch cards were one of the earliest forms of data storage and programming of computers. Learn more.