Outstanding and fun article here on early computer bugs:
The world first computer "bug"
By Grace Hopper, a.k.a. "Amazing Grace":
"On September 9, 1945, U.S. Navy officer Grace Hopper found the first computer "bug": a moth stuck between the relays on the Harvard Mark II (successor to the Mark I above)
She noted it on her log as the "first actual case of bug being found." Though the term "bug" had meant a computer error beforehand, it became a popular term after this incident."