The word ‘bug,’ when applied to computers, means some form of error or failure. On September 9th, Grace Hopper records what she jokingly called the first actual computer bug — in this case, a moth stuck between relay contacts of the Harvard Mark II computer.

Hopper helped program the Mark II, and the earlier Harvard Mark I computer, while working for professor Howard Aiken. She worked tirelessly on developing these computers to the fullest through inventive programming. After Harvard, she worked for computer manufacturer Remington-Rand where she developed what is often considered the first compiler, A-0. She also served on the committee to develop COBOL, a standard and widely adopted programming language that transformed the way software was developed for business applications. COBOL is still in use today. Hopper was made a Fellow of the Computer History Museum in 1987.