The world's first computer bug is recorded - September 9th, 1947

On this day in 1947, a team of engineers at Harvard University reported the earliest known computer bug.

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Episode Transcript

Speaker 1 (00:00):
This Day in History Class is a production of I
Heart Radio. Hello and welcome to This Day in History Class,
a show for those who can never know enough about history.

(00:20):
I'm Gabe Bluesier, and today we're looking at the time
when early computer scientists encountered an unusual problem with their hardware.
The day was September nine. A team of engineers at

(00:44):
Harvard University reported the earliest known computer bug today. Debugging
computer systems and software is a routine step in computer
programming and software development. It's a way to find and
resolve potential errors or bugs and software code so that
the program or system is able to operate correctly. However,

(01:07):
the computer bug reported at Harvard wasn't a bad line
of code or a machine defect. It was an actual insect,
a brown house moth, to be precise. In the US
Navy contracted Harvard engineers to build and test an early
electro mechanical computer. The device was called the Ak and

(01:29):
Relay Calculator, also known as the Harvard Mark two, and
it was designed to make ballistic calculations. The machine was
completed in and the test phase went smoothly at first. However,
in early September, the team noticed the machine had started
registering consistent errors. On September nine, they opened the computer's

(01:52):
hardware to try and find the source of the problem.
That's when they saw it. Squashed between two points in
relay a number seventy of panel F was a small
dead moth. It had somehow gotten trapped inside the Mark too,
and once it had ceased to move, the weight of
its body disrupted the electronics and caused the computer to malfunction.

(02:14):
The team literally had to debug the machine to fix it,
and the irony of the moment wasn't lost on them.
Instead of discarding the pesky moth, the team preserved it,
taping it inside the Mark two's log book. Among the
team's members was skilled mathematician and computer language pioneer Grace

(02:35):
Murray Hopper. She had graduated from Yale University with a
pH d in mathematics in thirty four, and later became
a professor of the subject at Vassar College. She then
joined the Naval Reserves during World War two and began
working with very early computers at Harvard in four. Dr
Hopper was considered one of the top minds in her field,

(02:58):
with one of her greatest claims to aim being the
creation of the first English language data processing compiler. That
program was able to translate computer code written in one
programming language into another language, such as machine code. That
breakthrough allowed a programmer to write code using English commands,

(03:19):
making the process faster, easier, and less prone to error.
The discovery of the world's first computer bug took place
about five years before Hopper finished her compiler. She wasn't
one of the technical crew that found and removed the
dead moth, but she is believed to be the one
who taped it. Inside the log book. Alongside the moth,

(03:41):
Hopper recorded the time of day, three PM and the
location of the bug Relay seventy of Panel LEF. She
also included the tongue in cheek note that made the
incident famous. It said quote first actual case of bug
being found. Many sources have claimed that Grace Hopper actually

(04:03):
invented the term computer bug with that entry. However, the
note itself seems to suggest otherwise. After all, her corny
joke about it being the first actual case of a
bug doesn't make much sense if the term wasn't already
in common use. In reality, American inventors and engineers have
been referring to small mechanical flaws as bugs for more

(04:27):
than a century and a half. One of the earliest
recorded uses of the term comes from none other than
Thomas Edison. In November of eighteen seventy eight, he used
the phrase in a letter to Hungarian inventor Theodore Puscus
when describing an issue with his latest version of the phonograph.
Edison wrote quote, I have the right principle, and I'm

(04:49):
on the right track. But time, hard work, and some
good luck are necessary too. It has been just so
in all of my inventions. The first step is an
intuition and comes with a burst. Then difficulties arise, This
thing gives out, and then that bugs as such, little
faults and difficulties are called show themselves, and months of

(05:12):
intense watching, study, and labor are requisite before commercial success
or failure is certainly reached. No one knows who originally
coined the term bug, but Edison was certainly the one
to popularize it in relation to machinery or electronics. Late
nineteenth century newspaper sometimes referred to his use of the expression,

(05:33):
and by nine thirty four it had become so commonplace
that Webster's New International Dictionary added a third definition for
the noun bug, a defect in an apparatus or its operation.
So Dr Hopper and the rest of the team at
Harvard didn't invent the term, but since their work occurred
in the very early days of computers, they were likely

(05:57):
the first to apply it to that kind of machine.
As a result of their little joke, the words bug
and d bug soon became common lingo among computer programmers,
just as they had been among their nineteenth century predecessors.
In recognition of the first bug found in a computer,
September ninth is now celebrated around the world as Tester's Day.

(06:20):
And as for the infamous bug itself, it's still attached
to page ninety two of the Harvard Mark tow Log
Book and is now part of the permanent collection at
the Smithsonian's Museum of American History in Washington, d C.
Go check it out for yourself. Today's story is an
interesting intersection between etymology, the study of the origin of

(06:42):
words and their meanings, and entomology, the study of insects.
So before we go, I want to share a fact
that scholars of both fields will appreciate. Even though the
moth found in the Mark two was labeled the first
computer bug. Biologically speaking, it wasn't a bug at all.
That's because, contrary to popular belief, bugs and insects aren't

(07:06):
the same thing. Bugs are a specific type of insect
set apart by key biological differences. Bugs, for example, have
three life stages, while most other insects have four. By
this measure, aphids, cicadas, stink bugs, bed bugs, and water
bugs are all true bugs, but flies, bees, beetles, butterflies,

(07:28):
and yes, moths all belong to different orders and are
only classified as insects, not bugs. So yeah, for all
you purists out there, the Harvard moth was actually the
world's first computer insect. But come on, that's not nearly
as catchy. I'm gay, Bluesier and hopefully you now know

(07:50):
a little more about history today than you did yesterday.
You can learn even more about history by following us
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HC Show, and if you have any comments or suggestions,
feel free to send them my way at this day
at I heart media dot com. Thanks to Chandler Mays

(08:12):
for producing the show, and thank you for listening. I'll
see you back here again soon. For another day. In
history class,