Harvard, 1947
A room full of clicking.
Harvard's Mark II computer fills a room with switches called relays, clicking open and shut all day long.
Sept 9, 1947 · 15:45
BUGS
First actual case of bug being found.
The first computer bug was a real moth. Scroll to find it.
15:45
Something's wrong.
The answers coming out don't add up. The team starts hunting, panel by panel.
Panel F
Relay number 70.
One switch isn't closing the way it should. They lean in for a closer look.
The culprit
A moth.
A real one, wings and all, jammed between the contacts.
The logbook
Taped in, for history.
They stick it in the logbook with a note: first actual case of bug being found. The joke lands. The name sticks forever.
Mark II running
Up close
One page. One moth.
Keep scrolling to lean in.
More code, more bugs
From one relay to billions of lines.
1lines of code
0bugs hiding, roughly
One line
Countdown
June 4, 1996.
Europe's new Ariane 5 rocket on its very first flight. Scroll to launch.
T-10seconds
0value in a 16-bit box
Try it yourself
Find the bug.
One line in this code is wrong. Tap it before the timer runs out.
0bugs squashed
0in a row
Read carefully. Some of these broke real things.
level 120s
Take it apart
The anatomy of a bug.
Hall of bugs
Tiny mistakes. Huge headlines.
1878
Edison says "bug"
Thomas Edison writes about "bugs" in his inventions. Engineers were calling glitches bugs long before computers.
1947
The first actual bug
A moth in relay 70 of Harvard's Mark II gets taped into the logbook. Grace Hopper, who worked on the machine, made the story famous.
1962
Mariner 1
A tiny error in the guidance software sends NASA's Venus probe off course. It's destroyed minutes after launch.
1994
Pentium can't divide
A flaw in Intel's Pentium chip gives slightly wrong answers to some divisions. The recall costs Intel about $475 million.
1996
Ariane 5
A number too big for its box crashes the guidance system. The rocket breaks up 37 seconds after liftoff.
1999
Mars Climate Orbiter
One team uses pounds, the other newtons. The spacecraft flies too low and is lost at Mars.
2000
Y2K
Years stored as two digits threaten to turn 2000 into 1900. Programmers spend years fixing it in time.
2016
The DAO
A bug in a smart contract lets an attacker drain about 3.6 million ETH. Ethereum splits in two over how to fix it.
2024
The blue screen day
One faulty CrowdStrike update crashes about 8.5 million Windows computers, grounding flights around the world.
2038
The next Y2K
Older systems count time in a 32-bit number that runs out on January 19, 2038.
Next
Your bug
The logbook isn't finished. Someone reading this finds the next one.
Mars Climate Orbiter, 1999
Pounds or newtons?
One team's software reported thrust in pound-force seconds. The other expected newton-seconds. Every number was off by a factor of 4.45, and nobody noticed for nine months.
Arriving at Mars
Y2K and 2038
When the clock runs out of digits.
Save a year as two digits and 2000 looks like 1900. Count seconds in a 32-bit number and on January 19, 2038 it overflows and jumps back to 1901.
December 31, 1997
Every bug is a moth in a relay. Small, silly, and stuck where nobody looked. Find it, tape it in the book, and keep going.
Bug zapper
Catch them all.
Moths fly to the light. Tap them before they reach it. Scroll fast and the lamp gets brighter, so more of them come.
0flying
0caught
0reached the lamp
Today
The first bug turns 79.
It's been a long time since someone first pulled a moth out of a computer. Here's the count, live.
0years since the first bug
0days since then
0days to its next birthday
0days until the 2038 bug