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Reminds me of patriot missiles: > The Patriot missile battery at Dhahran had been in operation for 100 hours, by which time the system's internal clock had dri

Reminds me of patriot missiles: > The Patriot missile battery at Dhahran had been in operation for 100 hours, by which time the system's internal clock had drifted by one-third of a second. Due to the missile's speed this was equivalent to a miss distance of 600 meters. > The radar system had successfully detected the Scud and predicted where to look for it next. However, the timestamps of the two radar pulses being compared were converted to floating point differently: one correctly, the other introducing an error proportionate to the operation time so far (100 hours) caused by the truncation in a 24-bit fixed-point register. As a result, the difference between the pulses was wrong, so the system looked in the wrong part of the sky and found no target. With no target, the initial detection was assumed to be a spurious track and the missile was removed from the system. No interception was attempted, and the Scud impacted on a makeshift barracks in an Al Khobar warehouse, killing 28 soldiers, the first Americans to be killed from the Scuds that Iraq had launched against Saudi Arabia and Israel. So such things happen also in military (although this was early nineties) Source: https://en.m.wikipedia.org/wiki/MIM-104_Patriot https://en.m.wikipedia.org/wiki/MIM-104_Patriot

redis_mlc 5y ago
I have a feeling from following it that the early Patriot missile system was full of bugs. The Israelis later built their own system called Iron Dome, which implies the Patriot had more than minor problems with quick fixes. The Phoenix missile also didn't work as expected initially, but the Sidewinder always worked but has had about 10 revisions.
bellyfullofbac 5y ago
Ouch, imagine dying because of a rounding off error... More detail in 1 link from the article: https://web.archive.org/web/20100702180720/http://mate.uprh.edu/~pnm/notas4061/patriot.htm https://web.archive.org/web/20100702180720/http://mate.uprh....
- heavenlyblue 5y ago
  Taking a contrarian point of view: people die for far simpler reasons.
- interestica 5y ago
  Kind of related. I always found it interesting that the Terminator's heads up display noted no casualties as "0.0" -- and I always wondered how a computer/killing-machine from the future might calculate casualties. https://youtube.com/watch?v=oolP65DLQLY https://youtube.com/watch?v=oolP65DLQLY
35fbe7d3d5b9 5y ago
Which then reminds me of a classic: > I was once working with a customer who was producing on-board software for a missile. In my analysis of the code, I pointed out that they had a number of problems with storage leaks. Imagine my surprise when the customers chief software engineer said "Of course it leaks". He went on to point out that they had calculated the amount of memory the application would leak in the total possible flight time for the missile and then doubled that number. They added this much additional memory to the hardware to "support" the leaks. Since the missile will explode when it hits it's target or at the end of it's flight, the ultimate in garbage collection is performed without programmer intervention. https://groups.google.com/forum/message/raw?msg=comp.lang.ada/E9bNCvDQ12k/1tezW24ZxdAJ https://groups.google.com/forum/message/raw?msg=comp.lang.ad...
- mousepilot 5y ago
  that post contains a pretty serious error, the sig should start with two dashes and a space.

redis_mlc 5y ago

I have a feeling from following it that the early Patriot missile system was full of bugs. The Israelis later built their own system called Iron Dome, which implies the Patriot had more than minor problems with quick fixes. The Phoenix missile also didn't work as expected initially, but the Sidewinder always worked but has had about 10 revisions.

bellyfullofbac 5y ago

Ouch, imagine dying because of a rounding off error... More detail in 1 link from the article: https://web.archive.org/web/20100702180720/http://mate.uprh.edu/~pnm/notas4061/patriot.htm https://web.archive.org/web/20100702180720/http://mate.uprh....

heavenlyblue 5y ago
Taking a contrarian point of view: people die for far simpler reasons.
interestica 5y ago
Kind of related. I always found it interesting that the Terminator's heads up display noted no casualties as "0.0" -- and I always wondered how a computer/killing-machine from the future might calculate casualties. https://youtube.com/watch?v=oolP65DLQLY https://youtube.com/watch?v=oolP65DLQLY

35fbe7d3d5b9 5y ago

Which then reminds me of a classic: > I was once working with a customer who was producing on-board software for a missile. In my analysis of the code, I pointed out that they had a number of problems with storage leaks. Imagine my surprise when the customers chief software engineer said "Of course it leaks". He went on to point out that they had calculated the amount of memory the application would leak in the total possible flight time for the missile and then doubled that number. They added this much additional memory to the hardware to "support" the leaks. Since the missile will explode when it hits it's target or at the end of it's flight, the ultimate in garbage collection is performed without programmer intervention. https://groups.google.com/forum/message/raw?msg=comp.lang.ada/E9bNCvDQ12k/1tezW24ZxdAJ https://groups.google.com/forum/message/raw?msg=comp.lang.ad...

mousepilot 5y ago
that post contains a pretty serious error, the sig should start with two dashes and a space.