9 Software Disasters

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” If debugging is the process of removing bugs, then programming must be the process of putting them in. „

Edsger Dijkstra

How bugs lead to disasters

#1 Explosion of Ariane 5, 1996

“ Conversion of a 64 bit integer into a 16 bit signed integer lead to an overflow. „

#2 Loss of Mars Climate Orbiter, 1999

“ Mix-up between pounds and kilogram. „

#3 Mars Polar Lander, 1998

“ Software error that mistakenly identified the vibration caused by the deployment of the lander's legs as being caused by the vehicle touching down on the Martian surface. „

#4 Loss of Mariner 1, 1962

“ Period instead of comma in FORTRAN DO-Loop. „

#5 Breakdown of AT&T’s long-distance telephone network, 1990

“ A single line of buggy code in a complex software upgrade implemented to speed up calling caused a ripple effect that shut down the network. „

#6 USS Yorktown dead in the water, 1998

“ Input and Division by ‘0’. „

X / 0 = undefined

#7 MIM-104 Patriot Missile Failure, 1991

“ Rounding Error „

#8 Shutdown of 5 nuclear reactors, 1985

“ Use of arithmetic sum of variables instead of the square root of the sum of the squares of the variables. „

∑ ≠ √

#9 Denver International Airport, 1994

“Baggage handling system broke down because of numerous bugs.”

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