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ArticlesNotorious Bugs


September 1995 / 20th Anniversary / Notorious Bugs

Bugs in computer hardware and software are no more than the crystallization in silicon and plastic of the mental mistakes all people make. People are only human, after all, so computers can only reflect our own humanity.

THE BUG THAT NEVER WAS, THANK HEAVEN

1983: The SDI (Strategic Defense Initiative) proposal was intended to defend the U.S. against a nuclear missile attack by using computer-aimed weapons to shoot down the missiles. It was estimated that the software would have required some 10 million to 100 million lines of code. Without the Soviet Union's cooperation in staging nuclear missile attacks to test it, the system would have to work perfectly--bug-free--the first time it was ever used. Despite widespread misgivings, a 1986 Department of Defense panel concluded that the concept was still feasible.


CHECK BOX TO PREPAY

1985: An IRS computer error resulted in 27,000 companies receiving warning notices to pay employee federal withholding taxes that they had, in fact, already paid. The House and the Senate planned hearings to investigate.


THE BUG THAT KILLED

1985-1987: At least four people died when they were exposed to lethal doses of radiation from Therac-25 linear accelerator machines (made by Atomic Energy of Canada Ltd.), used for radiation treatment of cancer. Software errors caused the machines to incorrectly calculate the amount of radiation being delivered to the patient. The most tragic incident to date of death or injuries to human beings due to defective computer software, this incident is a reminder that, as we entrust human lives and health to computers, the seriousness of eliminating bugs becomes a life-or-death proposition.


A BUG IN A WORM IN A NET

1988: A math error caused a "worm" program to multiply 14 times faster than intended, and as a result, the Internet was swamped and overwhelmed in a few hours. It was weeks before affected systems recovered from the damage wrought, costing in the hundreds of millions of dollars. Robert T. Morris, Jr., the Cornell University graduate student who wrote and unleashed the worm, later said, "It was a mistake. I'm sorry."


COMPUTER'S DOWN, CHECK YOUR PITONS

1988: Backup data, corrupted due to software errors, eventually destroyed all the main system data--and backup copies of data--at an automated Black & Decker distribution center in Northampton, England. Employees were eventually forced to climb the racks of inventory in the unlit warehouse with mountain-climbing equipment to check stock.


TO WHOM IT MAY CONCERN...

1989: A computer in Paris read files on traffic violations and then mistakenly sent out letters charging 41,000 traffic offenders with crimes including murder, drug trafficking, extortion, and prostitution. Recipients were described as "surprised."


WHY DOESN'T THIS EVER HAPPEN AT OUR BANK?

1989: A British bank that understandably wishes to remain nameless mistakenly transferred an extra 2 billion to customers in only 1 hour, when a bug permitted payment orders to be issued twice. Since there was no way to distinguish real from duplicate transactions, the bank had to depend on the honesty of its customers to recover the extra payments.


DIAL B FOR BUG

1990: A logic error in its call-handling computers shut down AT&T's long -distance telephone network for 9 hours, the most severe breakdown in the history of the U.S. telephone system. Some 74 million long-distance and 800-number calls were not completed, bringing phone-dependent businesses--like car, hotel, and airline reservations systems, and credit-card approval services--to a standstill.


SIN OF OMISSION

1991: American Patriot missiles were fairly successful. However, the failure of some Patriot missiles to track and destroy Iraqi Scud missiles during the Persian Gulf War may have been due to a software problem of the system. During one such Iraqi missile attack, 28 American soldiers were killed in their barracks in Dhahran, Saudi Arabia.


A BETTER WINDOWS THAN DOS

1991: With the introduction of Microsoft Windows 3.0, "unrecoverable application error" became a household phrase, soon to be replaced by "g eneral protection fault" in version 3.1 (heralded by the headline "Windows Upgrade Crashes Less Often").


DON'T USE THE CALCULATOR! WE NEED THE RIGHT ANSWER!

1991: It was revealed in 1994 that the Calculator applet in Microsoft Windows did not display correct answers. Reportedly, it took the Pentium bug brouhaha to motivate Microsoft to admit and fix a bug it may have known about since 1991.


YOU ARE LOST AND GONE FOREVER...

1993: An $80 million satellite called Clementine was hopelessly lost in space after a software error caused its thruster rockets to fire continually, consuming all its fuel before its asteroid-rendezvous mission was completed.


DOUBLE, DOUBLE, TOIL AND TROUBLE

1993: The DoubleSpace automati hard disk comparision software included in Microsoft MS-DOS 6.0 -- billed as capable of nearly doubling the effective space on hard drives -- corrupted data, was incompatible with certain BIOSes, and crashed programs and networks. Besides which, Microsoft lost a compression patent-infringement suit brought by Stac Electronics, to the tune of over $100 million. (Of course, it later struck a partnership with Stac.) Version 6.2, which cleared up the majority of these problems, was denied to be a "bug fix."


DON'T EVEN LEAVE THE AIRPORT

1994: For months, bugs in a computerized baggage-handling system delayed the opening of the new Denver airport. The system would drive automated baggage carts into walls or deposit bags at the wrong airport destination. After an additional expenditure of some $80 million to fix the system, the airport finally opened in February 1995 -- with a manual baggage-handling system that will be phased out gradually. Sometimes you just can't beat the human touch.


DIVIDING WE FALL

1994: The Pentium bug, probably the most widely reported-on bug in history, was a glitch in the lookup table used to perform floating-point division in Intel's flagship chip. The magnitude of errors ranged from 1 out of 10,000 to 1 out of 1 quadrillion, while estimates of the frequency of errors varied widely from days to millennia. Probably more significant than the defect itself was the fact that Intel's reputation was tarnished needlessly: Intel knew about the problem, decided to keep it a secret, and then downplayed the defect when it was discovered independently. It is estimated that Intel may have lost upward of $400 million due to the Pentium bug.


OH, I JUST CAN'T WAIT TO BE (WOR)KING

1994: Disney Interactive was the cause of some Christmas-morning traumas when its Lion King animated story CD-ROM, easily the most-anticipated and best-selling title during that season, wouldn't work. Inadequate testing by third-party developers caused installation failures on many PC systems. This may have been the first bug to affect popular culture.


AND ON WALL STREET, 166 FUNDS REMAIN UNCHANGED

1994: One day, Fidelity Investments, the $250 billion mutual fund corporation, was temporarily unable to calculate the "net asset value" for 166 of its 208 mutual funds because a bug had overwritten every stock in its database with 9s. A low-level employee authorized using the closing prices of the previous day rather than admitting that Fidelity didn't know what the actual prices were. The subsequent uproar resulted in the establishment of rules for handling such situations in the future.


THE INCREDIBLE GROWING FILE

1994: A bug in CorelDraw 5 caused the size of a file to multiply wildly when certain operations were performed, transforming 2-MB files into 30-MB behemoths. Although fixed in subsequent releases, another file size problem later emerged.


THREE OF LIFE'S CERTAINTIES: DEATH, TAXES -- AND BUGS

1994-1995: Intuit announced that calculation errors or loss of data could occur in both its TurboTax and MacInTax income tax preparation programs. Many people use such programs because they are worried about making errors by doing their taxes manually.


ABSOLUTELY, POSITIVELY DELETED

1995: Millions of Super Bowl telecast watchers were impressed by ads for Federal Express's new Windows software for handling package pickup and keeping track of FedEx deliveries. Unfortunately for the estimated 15,000 companies that started using the first release, all their records were deleted on the first day of each month.


THE BUG IS YET TO BE

2000: When the global odometer turns over on January 1, 2000 A.D., computer systems the world over are expected to buckle. Legacy mainframe programs hard-coded to treat the year "00" as 1900 will begin calculating negative ages, seniorities, and benefits. Where will your bet be when the millennial roulette wheel comes up "00"?


Up to the 20th Anniversary section contentsGo to previous article: A Brief History of Programming LanguagesGo to next article: Best Computer ShowsSearchSend a comment on this articleSubscribe to BYTE or BYTE on CD-ROM  




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