The Machine That Started It All: Inside the World’s First Electronic Computer

By moshikhosi | Revolutionizing Of Computing | 10 May 2025

From Dreams to Diodes

Imagine a world where calculations that take seconds on your phone once needed days of physical labor. Complex calculations like World War II artillery trajectories were done by hand or with mechanical devices before the digital revolution. This changed permanently in the mid 1940s with the introduction of the ENIAC, the world’s first general purpose electronic computer.

This isn’t just a narrative about circuits and codes; it’s about how human creativity established the framework for the digital age.

The Genesis of the ENIAC

John W. Mauchly and J. Presper Eckert of the University of Pennsylvania created ENIAC, short for Electronic Numerical Integrator and Computer. Funded by the United States Army during World War II, the project intended to provide a speedier approach to calculate ballistic trajectories.

Construction began in 1943 and was completed in late 1945, just after the war ended. On February 15, 1946, ENIAC was publicly unveiled—changing the computing world forever.

What Made ENIAC Revolutionary?

1. Fully Electronic Operation

Unlike prior mechanical or electromechanical machines, ENIAC employed vacuum tubes—over 17,000 of them—to accomplish calculations. This accelerated it thousands of times quicker than its forebears.

2. Programmability

Although programming ENIAC was no trivial operation (requiring physical rewiring and switch flipping), it was programmable—a key step toward contemporary computing.

3. Scale and Power

ENIAC could execute 5,000 additions or subtractions per second, 357 multiplications, and 38 divisions—a stunning performance at the time.

It weighed almost 30 tons, occupied 1,800 square feet, and utilized 150 kilowatts of electricity. You’d need a small power plant to run it today!

Women Behind the Machine

ENIAC's initial programmers: Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas, and Ruth Lichterman.

Often ignored in history, six talented women were the initial ENIAC programmers. With no manuals or programming languages to help them, these women Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas, and Ruth Lichterman—taught themselves how to make ENIAC run. Their achievements created the framework for software engineering.

ENIAC’s Legacy

ENIAC was discontinued in 1955, but its significance remains undeniable:

Birth of Computer Science: It triggered an explosion of research into computing and electronics.

From Hardware to Software: It introduced the idea of storing and reusing programs, which influenced the stored-program architecture used in practically all computers today.

Commercial Computing: Led to the creation of future machines like UNIVAC, which established the commercial computer industry.

Fun Facts About ENIAC

The machine featured almost 5 million soldered joints.

Debugging sometimes entailed utilizing oscilloscopes and practically crawling inside the machine.

One of ENIAC's earliest duties was computing hydrogen bomb simulations.

Conclusion: A Spark That Ignited a Digital Firestorm

ENIAC was not only a computer—it was the birth cry of the information era. From 30-ton machinery to pocket-sized devices, we’ve gone a long way. But without the pioneering work of Mauchly, Eckert, and the six women behind ENIAC, the world may have taken a different road.

So every time you ask Siri a question or run a Python script, take a moment to honor the giants whose shoulders we stand on.