1950s mechanical calculator crumbles in the face of divide-by-zero conundrum — relic spins its gears uncontrollably in 'chaotic loop' of endless motion

1950s mechanical calculator
(Image credit: Vixhal)

Divide by zero is one of computing’s most notorious error conditions. Yet even before the digital age, divide by zero calculations could cause mechanical calculators to be thrown into chaos by the impossible, or more correctly, this ‘undefined operation.’ A striking example is provided by a video clip shared by mathematics and science enthusiast Vixhal on X, embedded below. The 1950s technological marvel spins its gears wildly and appears to be screaming “oil me, switch me off,” after being commanded to journey into mathematical oblivion.

Nevertheless, the Busicom 141-PF calculator, which was the first commercial product to be powered by the Intel chip, included firmware to detect divide by zero and show an error message. That’s a far preferable outcome to crashing, entering into an endless calculation loop, or exhibiting other unexpected behavior.

Hardware-level divide‑by‑zero exceptions weren’t present until Intel’s pioneering 8086 processor was launched in 1978. The famed first x86 architecture CPU introduced a native DIV instruction – as well as raising a DE exception, a hardware response, when a divisor of zero was detected.

Intel’s move helped protect computing applications from stumbling over divide-by-zero issues to some degree. However, another important step on the path to neutralizing such issues came in 1985, with the IEEE 754 standard adding floating‑point handling, producing Infinity or NaN instead of crashing. This would debut in mainstream hardware, starting with the Intel 80387 math coprocessor.

WoW & Raptor Lake INT_DIVIDE_BY_ZERO crashes in 2025

In 2025, while modern OS kernels can catch divide-by-zero exceptions at the hardware level, preventing crashing and unexpected behavior, some apps and games can still have issues if devs haven’t anticipated such a condition. Reddit and forum posts from World of Warcraft (WoW) players, as recently as a few months ago, suggest that there were INT_DIVIDE_BY_ZERO crashes in the game on Raptor Lake/Refresh CPUs that were still occurring earlier in 2025.

But, if you face an app or game crash in 2025, perhaps think about the poor 1950s mechanical calculator as you restart.

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Mark Tyson
News Editor

Mark Tyson is a news editor at Tom's Hardware. He enjoys covering the full breadth of PC tech; from business and semiconductor design to products approaching the edge of reason.