The Moth in the Computer
A moth once became part of computer history—not by flying across a screen, but by getting stuck inside a machine. On September 9, 1947, workers at Harvard University recorded an unusual discovery in the logbook for the Harvard Mark II computer. They found a moth in one of its electrical parts and taped the insect to the page.
The Mark II was very different from a laptop or tablet. It was a large machine that used many relays. A relay is an electrically controlled switch. As these switches opened and closed, the computer could carry out steps in a calculation. If a relay failed to work properly, the machine might not perform those steps as intended.
The moth was found in a relay. The logbook entry recorded the location and described the insect as the first actual case of a bug being found. It was a joke as well as a record: the word bug was already used for a problem in a machine or system. This particular bug happened to be an insect.
- calculation:
- The process of working out an answer using numbers.
- operation:
- The way something works or is used.
- observation:
- Something noticed and recorded.
- explanation:
- A statement that tells how or why something happens.
- evidence:
- Information that helps show whether an idea is true.
- preserve:
- To keep something safe so it lasts.
- unintended:
- Not planned or meant to happen.
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Preview questions from this passageShowHide
- 1Why was finding a moth in the Mark II relay especially memorable?
- 2How did relays help the Mark II carry out calculations?
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About this explanatory article passage for Upper Elementary
“The Moth in the Computer” is a explanatory article reading passage about Computer history, written for Upper Elementary. It takes about 4 minutes to read (542 words) and comes with an interactive quiz and a printable worksheet with comprehension questions and an answer key.