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The Big Technical Mistakes of History
An anonymous reader tips a PC Authority review of some of the biggest technical goofs of all time. "As any computer programmer will tell you, some of the most confusing and complex issues can stem from the simplest of errors. This article looking back at history's big technical mistakes includes some interesting trivia, such as NASA's failure to convert measurements to metric, resulting in the Mars Climate Orbiter being torn apart by the Martian atmosphere. Then there is the infamous Intel Pentium floating point fiasco, which cost the company $450m in direct costs, a battering on the world's stock exchanges, and a huge black mark on its reputation. Also on the list is Iridium, the global satellite phone network that promised to make phones work anywhere on the planet, but required 77 satellites to be launched into space."
Don't forget the Therac-25
Poor software design and development led to radiation overdoses for 6 patients being treated for cancer, with 3 dying as a direct result.
Sadly, mistakes still keep on happening.
You're probably having it quite often without even knowing it. Latency to low-earth isn't the same as geostationary.
it's in my head
Yeah, I would immediately classify any error that caused deaths to be more important.
Another interesting case was the Patriot Missile failure. The system clock counted in 1/10th second increments. However, it added 0.1 to a floating point number. Unfortunately, 0.1 in binary is a repeating number, similar to 1/3rd in binary being 0.333333333...
So, ten times every second the time drifted just the tiniest bit. The missile that missed had been running for days, so its clock was one third of a second off, and a Scud travels a long way during that time.
Let that be a lesson to all of you: use an integer counter, and divide by 10 to get the time in seconds.
Write your representatives! Repeal the 2nd Law of Thermodynamics!
One-in-a-few-billion problem ?
At that time, I was programming a network game about trucks, and when when replaying a demo on the network, the players desynchronized after a few minutes.
I spent a lot of time looking into the logs, and discovered that there was a floating point error that desynchronized the trucks.
I still believe that the FDIV bug was much more frequent than publicized, and it had more impact than what Intel originally described.
Intel released a software patch to Watcom C++ library, but the patch was terrible, with the FDIV replaced with a lot of instructions just to detect the cases where the bug might appear, and use shiftings instead of FDIV.
I think that the bug was much publicized because it was the beginning of Internet, where a lot of new information went unfiltered, and Intel completely missed their communication on this bug discovered by Thomas Nicely.
Here is the whole story behind this bug:
http://www.trnicely.net/pentbug/pentbug.html