The ENIAC: A Room-Sized Computer
The Electronic Numerical Integrator and Computer (ENIAC), completed in 1945, was the first general-purpose electronic computer. It was massive, occupying 1,800 square feet of floor space and weighing 30 tons – truly a room-sized machine.
The Scale of ENIAC
ENIAC was enormous by modern standards. It contained over 17,000 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors, and approximately 5 million hand-soldered joints. It consumed 150 kilowatts of electricity – enough to power hundreds of modern computers.
The machine was so large that it required its own dedicated building. It stood 8 feet tall, 3 feet deep, and 80 feet long – about the size of a small house. Despite its massive size, ENIAC’s computing power was less than that of a modern pocket calculator.
What ENIAC Could Do
ENIAC was designed to calculate artillery firing tables for the U.S. Army during World War II. It could perform 5,000 additions or 357 multiplications per second – impressive for its time, but incredibly slow compared to modern computers that can perform billions of operations per second.
The machine was programmed by physically rewiring it – there was no software as we know it today. To change what the computer did, engineers had to manually reconfigure thousands of switches and cables, a process that could take days.
The Development Team
ENIAC was developed by J. Presper Eckert and John Mauchly at the University of Pennsylvania. The project was funded by the U.S. Army, which needed faster ways to calculate ballistic trajectories. The machine was completed too late to help with World War II, but it was used for calculations related to the hydrogen bomb.
Interestingly, many of ENIAC’s programmers were women – Kay McNulty, Betty Jennings, Betty Snyder, Marlyn Wescoff, Fran Bilas, and Ruth Lichterman. These “ENIAC girls” were among the first computer programmers, though their contributions were often overlooked at the time.
ENIAC’s Legacy
Despite its limitations, ENIAC proved that electronic computers were feasible and useful. It demonstrated that complex calculations could be automated, paving the way for the development of smaller, faster, and more powerful computers.
The machine was used until 1955, when it was dismantled. Parts of ENIAC are now on display in museums, including the Smithsonian Institution. The computer that once filled an entire room can now be represented by a single microchip smaller than a fingernail.
The Evolution of Computing
ENIAC represents the beginning of the computer age. In the 75+ years since its completion, computers have shrunk from room-sized machines to devices that fit in our pockets, while becoming millions of times more powerful.
Modern smartphones have more computing power than all of NASA’s computers combined during the Apollo moon missions. A single modern processor chip contains billions of transistors – more than all the components in ENIAC combined.
The journey from ENIAC to modern computers illustrates one of the most dramatic technological transformations in human history. What once required a dedicated building and a team of engineers can now be accomplished by a device that fits in your hand.
ENIAC’s story reminds us of how far computing has come and how rapidly technology can evolve. It also highlights the importance of preserving and understanding our technological history, as it helps us appreciate the incredible devices we use today.