The Electronic Numerical Integrator and Computer (ENIAC) was first unveiled to the public today in 1946. Constructed and operated at the The Moore School of Electrical Engineering at the University of Pennsylvania, ENIAC became a huge milestone in computing as “the first general-purpose electronic computer.” ENIAC was massive in stature, a Goliath in power consumption, and unassailable in compute power at launch. However, in 2026, its 18,000 vacuum tube-powered performance seems laughable compared to even the lowliest throwaway consumer electronics.
ENIAC’s performance
While we can no longer marvel at ENIAC’s compute prowess, it was around 1,000x faster than its nearest rivals in the mid 1940s. ENIAC could perform around 5,000 calculations per second, allowing humans to tap into math at electronic speed for the first time.
This first general-purpose electronic computer was used to perform a variety of tasks. However, as ENIAC was funded by the U.S. military, some of its best-known compute tasks include calculating artillery trajectories.
“The ballistics calculation that previously took 12 hours on a hand calculator could be done in just 30 seconds,” notes the Penn Engineering blog. ENIAC was also used in H-bomb calculations, ballistic missile and rocket calculations, for weather prediction experiments, and more.
Programming ENIAC was done via a combination of plugboard wiring and a trio of portable function tables, each bristling with 1,200 ten-way switches. So, mapping a problem to run on ENIAC was a far from trivial task, which usually took highly trained teams several weeks, plus extensive testing, verification, and debugging.
"Jean Bartik (left) and Frances Spence operating the ENIAC’s main control panel. Bartik was present on the day of ENIAC’s unveiling to the world, and even helped troubleshoot a switch issue the night before its unveiling, but her efforts, and those of ENIAC’s five other women programmers, were nearly forgotten." (Image credit: University of Pennsylvania
ENIAC specifications
Though its architecture is rather different from that of a modern computer, it is interesting to look at the construction and component specs that formed the ENIAC.
In terms of its physical presence and build, an ENIAC Top Trumps card might be an ace… It featured 8,000 vacuum tubes, 70,000 resistors, 10,000 capacitors, and 500,000 soldered joints, with dedicated power lines delivering 150kW of electricity. Naturally, ENIAC was huge and heavy, too. The Penn Engineering blog says that it occupied a 30 x 50 foot room and weighed 30 tons.
... continue reading