© Mark Ollig
In 1947, a team of engineers, including computer pioneer and programmer Grace Murray Hopper, discovered the cause of the problem preventing electrical current from flowing through a circuit.
The circuit was inside the ten-foot-high, 3,000-square-foot Harvard Mark II electromechanical computer built in 1945 and located at Harvard University in Cambridge, MA.
Hopper was undoubtedly surprised upon discovering the cause of the current-flow interruption between the metal conducting points on one electromagnetic relay.
The culprit was a moth that had become stuck in the relay, interrupting circuit flow.
Removing the moth allowed the flow of current through the relay, which resumed its regular operation.
The Harvard Mark II computer operations logbook update read, “Relay #70 Panel F (moth) in relay.”
The cause of the problem, a Lepidopteran insect, in this case, a moth, was taped on the logbook page with the following note, “First actual case of bug being found.”
Over the years, credit has been given to Hopper for originating the frequently used phrase “I found a bug in the computer.”
The computer terms “bug” and “debugging” became commonly used in the early 1950s and 1960s.
I learned the word “bug,” used in a technical sense, was first coined by Thomas Edison during the 1870s while working on a quadruplex electrical telegraph.
Hopper has been recognized for popularizing the computing term “bug” since her team found an actual bug causing a computer problem.
On Sept. 9, we will observe the 75th anniversary of the bug she and her team debugged from a computer.
Within some computing circles, folks still debate whether a moth should be considered a bug or an insect.
The encyclopedia says moths are in the butterfly family, belonging to the order of Lepidoptera, which are nocturnal flying insects.
High school biology class taught us insects are in the Insecta class, which is part of the phylum Arthropoda group.
“I found a bug in my computer,” or, “I found an insect in my computer.”
I will go with “bug.”
Many (very many) years ago, this columnist regularly worked with an electromechanical switching platform using electromagnetic relays.
From 1960 until the end of 1986, the telephone company in Winsted provided dial-tone telephone calling services using a GTE-Leich TPS (terminal per station) electromechanical relay-operating telephone switching system.
Some of my readers may remember being given a tour of the telephone switching system when you stopped by the office or were in school and visited as part of a class trip.
Tall rows of cabinets containing electromechanical relay bars once filled the central office of the Winsted Telephone Company.
The 11-foot-high by 4-foot-wide steel frames housed cabinet bays wired with hundreds of vertically-positioned electromechanical relay bars, with some having thin, carbon filament lamps glowing during electrical circuit activity.
Every cabinet bay was enclosed with a thin metal frame and a clear plastic cover to protect the relay bars’ circuitry.
Each bar measured approximately three feet tall by four inches-deep by 3-inches-wide and contained five to twenty individual relays of various sizes.
A person could determine how busy the telephone switching system was processing phone calls by the number of glowing carbon filament lamps and the audible level of relays clicking.
The more lights and clicking, the higher the processing volume of telephone calls.
Over time, carbon-like oxidation would build up on the relay contact points, acting as an insulating agent and thus preventing electrical current flow.
We used a burnishing tool with a very fine sandpaper-like abrasive on a thin metal strip to remove this oxidation.
While moving the burnishing tool in a back-and-forth, filing-like motion, we would lightly sand off the oxidation covering the metallic contacts of the relay.
Accumulation of dust could also interfere with a relay’s operation.
Part of our central office preventive maintenance included scheduled dust-removal cleaning of individual relay bars.
During routine maintenance or repair, we removed an electromechanical relay bar and took it outside (usually on the sidewalk in front of the telephone office).
We sprayed high-pressured air onto the relay contacts using a portable air compressor to blow away any dust or small particles.
So that you know, we never found any bugs or insects between the metal conducting contact points of the relays.
There may be a few of these old-fashioned electromechanical relay-operating telephone switching platforms still working; however, I doubt it – unless they are in a museum.
The Harvard Mark II computer operations logbook (including the moth) is kept in the History of American Technology Museum of the Smithsonian in Washington, DC. You can see this page at https://s.si.edu/3z74ewy.
Grace Murray Hopper, recognized as one of the first to “debug” a computer, was born on Dec. 9, 1906, in New York City, NY. She died on Jan. 1, 1992, and is buried at Arlington National Cemetery in Virginia.
My video of a never-used, 62-year-old electromechanical relay-operating “firebar” from the Winsted Telephone Company can be seen at https://bit.ly/3Bc6lSe.
Here is to hoping none of you will find any bugs (or insects) in your computer, relays, or bed.
