The first documented computer bug was a real moth found inside the Harvard Mark II computer in 1947. This surprising fact may sound like a joke, but it is a verified historical event that played an important role in shaping modern computing terminology.
Today, words like “bug” and “debugging” are part of everyday tech language. However, their widespread use in computing can be traced back to a very unusual incident involving an early electromechanical computer.
What Happened in 1947
On September 9, 1947, engineers were working on the Harvard Mark II Aiken Relay Calculator, a large machine used for complex calculations. When the computer started producing errors, the team investigated the cause and discovered a moth trapped inside one of the machine’s relays.
The insect was blocking an electrical connection and causing the malfunction. After removing it, the engineers taped the moth into the official logbook and wrote a note describing it as the first actual case of a bug being found. This logbook page is still preserved today at the Smithsonian National Museum of American History.
Did This Create the Term “Bug”?
The incident did not invent the word “bug.” Engineers had been using the term for technical problems long before computers existed. Even in the late 1800s, inventors such as Thomas Edison used “bug” to describe mechanical faults.
What made the 1947 event special was that it became the first documented case of a literal insect causing a computer malfunction. Because of its humor and clarity, the story spread widely and helped popularize the terms “bug” and “debugging” in computing.
Why Early Computers Were So Fragile
Early computers were very different from modern devices. They were large, open machines with many moving parts, which made them sensitive to their surroundings.
- They used mechanical relays instead of microchips
- Internal components were exposed to air and dust
- Small physical objects could easily disrupt operations
Why This Tech Fact Still Matters
This story is a reminder that technology evolves through real-world challenges. It shows how even a tiny moth could affect a massive machine and how a small moment in history helped define the language of modern computing.
The Harvard Mark II moth remains one of the most memorable symbols of early computer history and a fascinating example of how tech terms often have very human origins.