The acronym ENIAC stands for Electrical Numerical Integrator And Calculator.

The fact that it was simpy a numerical computer means it probably could be used to perform numerical integration in some form or other, but I wonder why "Numerical Integrator" was put in the name explicitly.

Were there specific design aspects of the computer that made it particularly suitable for performing numerical integration?

1 Answer 1


It's necessary to consider the standards of the time the machine was named, and its original purpose, which was calculating ballistics tables for the Ordnance Corps of the US Army. It replaced 200 people using mechanical calculators, and was faster and more accurate at that work. So what seem like very basic functions for supporting numerical integration now were revolutionary at the time.

From skimming the relevant chapter in The First Computers, edited by Rojas and Hashagen, MIT Press, the functions that were important for numerical integration seem to have been fast multiplication, and the "function tables", a set of controls for providing constants that could be read rapidly by the ENIAC's program. These weren't stored in memory, because ENIAC didn't have a memory in the modern sense.

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    Yes that makes perfect sense. I can see immediately how having function tables would be necessary for numerical integration when fast memory wasn't there yet. Even something like Runge–Kutta–Fehlberg (also here) needs a nice table of coefficients handy at each part of each step, higher order methods even more coefficients.
    – uhoh
    Feb 1, 2019 at 8:42

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