Better Software - December 2008 - (Page 46)

Software Bugs by Richard Bender the FiRst coMputeR BuG was saved Most people know the story of Grace Hopper and how on September 9, 1945, at 3:45 p.m. she discovered that a moth caught in the wiring of the Mark II computer was causing the machine to behave erratically. Thereafter, every time the computer behaved in an unexpected manner, her group said there must be another bug. However, most people do not know that Grace taped the moth into her log, which can be seen at history.navy.mil/ photos/pers-us/uspers-h/g-hoppr.htm. the teRM “BuG” in technoloGy pRedates soFtwaRe A newspaper report in 1889 stated that Thomas Edison “had been up the two previous nights searching for a bug in his phonograph.” Even earlier, in 1878, Edison writes to a friend that “Bugs show themselves, and months and months of anxious watching, study, and labor are requisite before commercial success – or failure – is certainly reached.” He sure sounds like a tester to me. Similarly, the term “debugging” predates the above mentioned moth. the Rate oF Residual BuGs is hiGh The residual bug rate (i.e., the defects left in the software after the testing has been “completed”) is five defects per thousand lines of executable code. If a high-end chip had this defect rate, it would be delivered with 5,000,000 defects. Residual BuGs aRe expensive In the US we spend about $350 billion a year on software including development, maintenance, packages, etc. The direct cost of dealing with these bugs is about $60 billion. The consequential costs exceed $290 billion. one BuG can cost Billions oF dollaRs A round-off error in calculating the market index for a Canadian stock exchange was not caught for twenty-two months. Since the calculation was performed 2,800 times a day, by the time it was caught it resulted in the index being miscalculated as half of what it should have been. This in turn drove the value of the stocks on that exchange down by a similar margin. soFtwaRe BuGs cause autoMoBile Recalls Hundreds of thousands of cars are recalled every year due to software bugs. Many of these are safety-critical issues such as the car’s disagreeing with the driver about stopping when the brakes are applied. a BuG was FeatuRed in people MaGazine In 1985, software bugs in the Therac-25 radiation treatment machine caused three deaths due to overdoses of radiation. soFtwaRe BuGs can Get you aRRested In 2004, a bug similar to no. 7 caused twelve patients in Panama to be overradiated. The developers and testers involved were arrested for murder by the Panamanian government, which also tried to extradite those who worked on the software in the US. soMe BuGs aRe theRe on puRpose In 1982, the CIA learned that the Soviets were trying to steal an oil pipeline process control system. So the CIA inserted a bug in it before letting the Soviets steal it. The result was the largest nonnuclear explosion ever seen up to that time. a BuG alMost destRoyed the woRld On September 26, 1983, a bug in a Soviet missile warning system made it appear that the US had launched a strike against them. A counterstrike to the phantom missiles was almost launched, which would have resulted in the destruction of a good portion of the planet. It was stopped by Lt. Col. Stanislav Petrov who refused to pass on the alert based on his hunch that it was a system bug. Lt. Col. Petrov is literally the man who saved the world. This list is extracted from a planned book called the Bender Book of Bugs. Additional bug stories are welcomed. Please send them to rbender@BenderRBT.com. 46 BETTER SOFTWARE DECEMBER 2008 www.StickyMinds.com http://history.navy.mil/photos/pers-us/uspers-h/g-hoppr.htm http://history.navy.mil/photos/pers-us/uspers-h/g-hoppr.htm http://www.StickyMinds.com

Table of Contents Feed for the Digital Edition of Better Software - December 2008

Better Software - December 2008 Contents Mark Your Calendar Contributors eLightenment Technically Speaking Code Craft Test Connection Management Chronicles What's a Manager to Do? Six Thinking Hats for Testers The Key to Good Interviewing 2008 Salary Survey Product Announcements 10 Things You Might Not Know About … The Last Word Ad Index

Better Software - December 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.