Thread by @PikumaLondon

This is one of my favorite folklore stories about computer #bugs!

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In the 1980s, Jake Poznanski had a programming mentor, Sergei, who was writing software for an SM-1800, a Soviet clone of the PDP-11.

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The computer was just installed at a railroad station near Sverdlovsk, a major USSR shipping center at the time. The new system was designed to route trains and cargo to their intended destinations, but there was a nasty bug that was causing random failures and crashes.

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The crashes would always occur once everyone had gone home for the night, but despite extensive investigation, the computer always performed flawlessly during manual and automatic testing procedures the next day.

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Usually, this indicates a race condition or some other concurrency bug that only manifests itself under certain circumstances. Tired of late-night phone calls from the station, Sergei decided to get to the bottom of it.

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He compiled a history of all occurrences of the unexplained crashes and plotted the dates and times on a calendar. Sure enough, a pattern was clearly visible! By observing the behavior for several days, he saw he could easily predict the timing of future system failures.

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He soon figured out that the rail yard computer malfunctioned only when the cargo being processed was live cattle coming in from northern Ukraine and western Russia heading to a nearby slaughterhouse.

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This was strange, as the local slaughterhouse had in the past been supplied with livestock from farms located much closer, in Kazakhstan.

The Chernobyl nuclear disaster occurred in 1986, spreading deadly levels of radiation making the nearby area uninhabitable.

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The radioactivity caused broad contamination in the surrounding areas, including northern Ukraine, Belarus, and western Russia. Suspicious of possibly high levels of radiation in the incoming train cars, Sergei devised a method to test his theory.

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Using a Geiger counter, they were able to measure one of the suspected rail cars, and they discovered the radiation levels were orders of magnitude above normal.

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Not only were the cattle shipments highly contaminated with radiation, but the levels were also high enough to randomly flip bits in the memory of the SM-1800, which was located in a building close to the railroad tracks.

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Read More: beza1e1.tuxen.de/lore/index.html