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Why Computers Suck At Math

antdude writes "This TechRadar article explains why computers suck at math, and how simple calculations can be a matter of life and death, like in the case of a Patriot defense system failing to take down a Scud missile attack: 'The calculation of where to look for confirmation of an incoming missile requires knowledge of the system time, which is stored as the number of 0.1-second ticks since the system was started up. Unfortunately, 0.1 seconds cannot be expressed accurately as a binary number, so when it's shoehorned into a 24-bit register — as used in the Patriot system — it's out by a tiny amount. But all these tiny amounts add up. At the time of the missile attack, the system had been running for about 100 hours, or 3,600,000 ticks to be more specific. Multiplying this count by the tiny error led to a total error of 0.3433 seconds, during which time the Scud missile would cover 687m. The radar looked in the wrong place to receive a confirmation and saw no target. Accordingly no missile was launched to intercept the incoming Scud — and 28 people paid with their lives.'"

4 of 626 comments (clear)

  1. Re:Poor QA by Stele · · Score: 4, Funny

    I guess in the Patriot situation, the decision went in the opposite direction. Hence errors we introduced.

    Ah, so you're the one responsible!

  2. Ridiculous. Patriots always win. by writermike · · Score: 3, Funny

    Look, you guys can talk trash all you want, but when you say this:

    >>Patriot defense system failing to take down a Scud missile attack

    You're just lying to yourself. The Patriots defense is awesome this year. I mean, was there really ANY point for the Titans offense to show up a couple of weeks back?

    And the Scuds? C'mon man. They let go their best man two seasons ago. The QB can't hit the broadside of a barn and their entire wide-receiver corp has Jello hands anyway. The missile attack is a gadget play, pure and simple. Belichick sees right through that and you know it.

    Haters need to stop all the hatin' and get on the Pats bus!!!!! GO PATRIOTS!

    --
    If Nalgene water bottles are outlawed, only outlaws will have Nalgene water bottles.
  3. Technically.... by CFD339 · · Score: 2, Funny

    ....I believe the aerobatic maneuver you describe is called the "Lawn Dart", and while it has been done many times in aviation history, few pilots have ever succeeded in doing it twice.

    --
    The problem with quotes on the internet, is that nobody bothers to check their veracity. -- Abraham Lincoln
  4. Re:God yes by symbolic · · Score: 3, Funny

    We even have a modern analog for this - the shift-lock key.