Kill switch

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This article is about the security device. For the video game, see kill.switch.

A kill switch (also called an e-stop) is a security measure used to shut off a device in an emergency situation in which it cannot be shut down in the usual manner. Unlike a normal shut down, which shuts down all systems naturally and turns the machine off without damaging it, a kill switch is designed to completely abort the operation at all costs.

[edit] Anti-piracy measure

Kill switch is a software anti-piracy feature, most notably in "Windows Vista" operating system. It renders software useless to users running pirated copy. Microsoft developed verification tool appropriately named "Windows Genuine Advantage", that activates kill switch on pirated software. In effect software kill switch is acting like electronic anti-theft system in cars, that disables stolen car.

[edit] Real world applications

A similar system, usually called a dead man's switch is used to shut down vehicles and machinery if the operator loses control or is ejected. A common example of this would be the kill switches used by boaters wherein a cord connects the kill switch to the operator (usually by their life jackets), and if the operator is thrown overboard in an accident, the cord will pull the switch and immediately shut down the vessels' engine.

A kill switch is also used for gasoline pumps or any other device that pumps large amounts of explosive or flammable chemicals. There is commonly a single kill switch for all pumps at a pumping station.

Kill switches are also used on land vehicles as an anti-theft device and as an emergency power off.

Also, an electronic musical instrument, such as a guitar or bass guitar, may have a kill switch. Used infrequently, but most commonly in heavy metal music, they break the circuit causing there to be no sound output. This is normally achieved by turning down the volume of one of the pick-ups then alternating the pick-up selector switch between that pick-up and one with the volume turned all the way up. They are sometimes used when a singer doubles as a guitar player and isn't playing or sometimes used as an effect during a song. Tom Morello of Rage Against the Machine and Audioslave is well known for his use of the kill switch.