Software bug history

The fix: engineers load the previous software release. A silicon error causes Intel's highly promoted Pentium chip to make mistakes when dividing floating-point numbers that occur within a specific range. For example, dividing Although the bug affects few users, it becomes a public relations nightmare. With an estimated 3 million to 5 million defective chips in circulation, at first Intel only offers to replace Pentium chips for consumers who can prove that they need high accuracy; eventually the company relents and agrees to replace the chips for anyone who complains.

A lack of sanity checks and error handling in the IP fragmentation reassembly code makes it possible to crash a wide variety of operating systems by sending a malformed "ping" packet from anywhere on the internet. Most obviously affected are computers running Windows, which lock up and display the so-called "blue screen of death" when they receive these packets.

But the attack also affects many Macintosh and Unix systems as well. June 4, — Ariane 5 Flight Working code for the Ariane 4 rocket is reused in the Ariane 5, but the Ariane 5's faster engines trigger a bug in an arithmetic routine inside the rocket's flight computer. The error is in the code that converts a bit floating-point number to a bit signed integer. The faster engines cause the bit numbers to be larger in the Ariane 5 than in the Ariane 4, triggering an overflow condition that results in the flight computer crashing.

First Flight 's backup computer crashes, followed 0. As a result of these crashed computers , the rocket's primary processor overpowers the rocket's engines and causes the rocket to disintegrate 40 seconds after launch. In a series of accidents, therapy planning software created by Multidata Systems International, a U. In the last century, software developers had never thought that their code and creations would survive into the new millennium.

Most decided to omit these two digits. The Y2K bug was real, nevertheless. Billions of dollars were spent in order to upgrade computer systems worldwide. Also, some small incidents were reported: In Spain, some parking meters failed. The French meteorological institute published on its website the weather for January 1st and in Australia, some bus-ticket validation machines crashed.

For a person, 0. The Mars Climate Orbiter was launched in with the goal of studying climate on Mars, although it never managed to fulfill its mission. After traveling through space for several months, the probe was destroyed because of a navigation error: teams who controlled the probe from Earth used parameters in imperial units meanwhile the software calculations were using the metric system.

These miscalculations had an impact on the flight path. In the end, the probe was destroyed because of friction with the Martian atmosphere an error of almost km. The problem in that case was, according to Google , a bug in the software that distributed load between its different data centers. The Gmail outage only resulted in people not having access to their email for a few hours. No one got killed. Nothing exploded. This article is about some of the more dire consequences of software errors through the years.

Incidents that make the Gmail outage seem rather trivial. In , a Soviet satellite reported incoming US missiles , but the officer in charge decided to follow his gut feeling that it was a false alarm and decided to do nothing. Luckily these false reports were never acted upon. If a counterstrike had been launched in either case, a full-blown nuclear war would have been a fact and the world would have been a very different place today. The hole in the ozone layer over Antarctica remained undetected for a long period of time because the data analysis software used by NASA in its project to map the ozone layer had been designed to ignore values that deviated greatly from expected measurements.

The Therac medical radiation therapy device was involved in several cases where massive overdoses of radiation were administered to patients in , a side effect of the buggy software powering the device. A number of patients received up to times the intended dose, and at least three of them died as a direct result of the radiation overdose.

Another radiation dosage error happened in Panama City in , where therapy planning software from US company Multidata delivered different doses depending on the order in which data was entered. Even a single typo can have unexpected side-effects. Cornell University grad student Roger Morris programmed the worm as an experiment meant to assess the size of the current internet and accidentally crashed approximately six thousand computers in a single day!

The computer program was meant to find connections between computers and pass the worm along, acting as a mapping tool, but the code failed to detect when it was already present on a computer.

First, always test for software vulnerabilities. The Morris Worm was able to exploit several known vulnerabilities in the ways Unix computers connected to each other to pass itself from one computer to the next.