Software bug: Difference between revisions

Revision as of 12:18, 27 May 2002

Revision as of 15:24, 27 May 2002

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There are bugs in all useful computer programs. However, well-written programs contain relatively few bugs, and these bugs typically do not prevent the program from performing its task. In contrast, "buggy" programs contain many bugs and/or bugs which interfere with the program's functionality.

Bugs have widely-varying effects. Some bugs have only a subtle effect on the program's functionality, and may thus lie undetected for a long time. More severe bugs may cause the program to [[crash]] or [[freeze (computing)|freeze]]. In some [[operating system|operating systems]], such as [[Microsoft Windows]], crashing or freezing programs may render the computer unusable until it is [[boot (computing)|rebooted]] (see [[Blueblue Screenscreen of Deathdeath]].) Other bugs lead to security vulnerabilities; untrapped buffer overflow is one common type of bug that often allows an attacker to execute a new program on the target machine with elevated privileges.

The cost of bugs may be considerable. [[Steve McConnell]] recounts several bugs that cost over US$100 million. The most spectacular case was Europe's [[Ariane 5]] rocket, which cost over US$1 billion. Shortly after launch, it was destroyed because of a bug in the on-board guidance computer.