In 1945, engineers found a moth in Panel F, Relay #70 of the Harvard Mark II computer system, which caused errors in its math functions. The moth was removed and taped into the computer's logbook with the words: "first actual case of a bug being found."
There have, of course, been many more computer bugs since, although usually in a less literal sense. Computer bugs can cause problems ranging from the trivial to the deadly. Wired examines their effects on our lives by listing the ten worst software bugs of all time.
The list includes:
The Mariner I Space Probe
A formula written on paper in pencil was incorrectly transcribed into computer code, causing a miscalculation the rocket's trajectory. It went off-course and had to be destroyed.
The Soviet Gas Pipeline
A bug in a Canadian computer system purchased to control the trans-Siberian gas pipeline caused the largest non-nuclear explosion in history. The bug may have been deliberately planted by the CIA.
The Therac-25 Medical Accelerator
A radiation therapy device malfunctioned, delivering lethal radiation doses at several medical facilities. At least five patients died; others were seriously injured.
The Kerberos Random Number Generator
An error in the security system's random number generator meant that for eight years, it was trivially easy to break into any computer relying on Kerberos for authentication.
The Intel Pentium Floating Point Divide
A silicon error caused Intel's highly promoted Pentium chip to make mistakes in certain division problems. Although the bug affected few users, it became a public relations nightmare, and ultimately cost Intel $475 million to replace the chips.
Ariane 5 Flight 501
A bug in an arithmetic routine caused a series of computer crashes, affecting the rocket's engines and causing it to disintegrating 40 seconds after launch.
National Cancer Institute, Panama City
A bug in radiation therapy planning software, activated when it was used in a nonstandard way, caused it to recommend twice the necessary radiation exposure. At least eight patients died, while another 20 received overdoses likely to cause significant health problems. The physicians, who were legally required to double-check the computer's calculations by hand, were indicted for murder.
