The invention of the ENIAC (Electronic Numerical Integrator and Computer) marked a turning point in computing history. Completed in 1945, ENIAC was the first fully electronic, general-purpose digital computer. Unlike earlier mechanical or electromechanical machines, ENIAC used vacuum tubes, making it exponentially faster and a direct ancestor of today’s digital computers.
Who Built ENIAC?
ENIAC was developed by John Mauchly, a physicist, and J. Presper Eckert, an electrical engineer, at the University of Pennsylvania. The project was funded by the U.S. Army during World War II, primarily to calculate artillery firing tables more efficiently.
Construction began in 1943, and the machine became operational in late 1945. It was formally unveiled to the public in February 1946.
ENIAC Specifications and Features
- Electronic Design:
- ENIAC used 17,468 vacuum tubes, along with thousands of resistors, capacitors, and relays. This allowed it to perform calculations about 1,000 times faster than electromechanical computers.
- Size and Power:
- Occupied about 1,800 square feet
- Weighed over 30 tons
- Consumed around 150 kilowatts of electricity
- Speed:
- It could perform 5,000 additions or subtractions per second, 357 multiplications per second, and 38 divisions per second — a massive leap in computational power at the time.
- Programming:
- ENIAC was not programmable in the modern sense. Instructions were manually set using switches, dials, and patch cables. Reprogramming could take days, as it involved physically rewiring parts of the machine.
- Decimal System:
- Interestingly, ENIAC used a decimal-based system (rather than binary), storing each digit as a series of electrical pulses.
Applications and Contributions
Initially designed for military use, ENIAC was later used for:
- Weather prediction
- Atomic energy calculations
- Wind tunnel design
- Ballistic trajectory modeling
- Mathematical studies like prime numbers
Its flexibility proved that electronic computing could be applied across disciplines — from physics to engineering and beyond.
Transition to Stored-Program Architecture
One major limitation of ENIAC was its lack of a stored-program capability — programs weren’t stored in memory. But in 1948, ENIAC was modified to include this feature based on concepts proposed by John von Neumann, who also worked with Mauchly and Eckert.
This transition pointed directly toward the von Neumann architecture, the foundational structure of modern computers, where program instructions and data share the same memory space.
Legacy and Recognition
ENIAC's impact on computing is monumental:
- It was the first truly high-speed electronic computing device.
- Its success inspired further development of machines like EDVAC and UNIVAC, the first commercial computer.
- The ENIAC programmers, a group of six women including Jean Bartik and Betty Holberton, became pioneers in software development — though their contributions were initially overlooked.
Today, ENIAC is recognized as the grandfather of modern digital computing, and its creators are honored in computing halls of fame worldwide.
Conclusion
The development of ENIAC was more than a technological achievement — it was the beginning of a digital revolution. Its speed, scale, and design introduced a new era where machines could process vast amounts of data in real time. Though primitive by today’s standards, ENIAC laid the foundation for the computing landscape we live in today — fast, programmable, and universal.