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23 December 2007

Why software testing is important - from New Scientist

Here is a story for those among us who do not believe that software testing is critical, this is from New Scientist's Doh! Of Technology:

Back to the future
IN FEBRUARY 2007, 12 F-22 Raptors, the US air force's new stealth fighters, left Hickam Air Force Base in Hawaii, bound for Okinawa, Japan, on the high-tech planes' first overseas outing. Things went smoothly until they reached the 180th meridian - otherwise known as the International Date Line.

Some of the pilots suddenly found themselves without any navigation aids. With nothing to tell them their compass heading or even whether they were level or not, it was as if the pilots had been instantaneously transported from the cockpit of the world's most advanced aircraft into one dating from the first world war.

Fortunately the skies were clear, so the squadron did an about-face and was able to follow its in-flight refuelling tankers back to Hickam.

The error was diagnosed as a problem with a "partial line of code" that had pitched the planes' computers into an infinite loop of trying and failing to calculate their position while dealing with an unexpected date. A fix was issued, and three weeks later the planes made their trip to Japan without a hitch.

"Reliance on electronics has changed the flight-test process," says
Donald Shepperd, once head of the US Air National Guard. "It used to be tails falling off, now it's typos that ground a fighter."


via Aide-mémoire

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