Big Red Button - Usages

Usages

• A shut-down switch for catastrophic circumstances to avert further damage or to cause it, e.g., an "emergency power-off" button.
• Help call in emergencies or for disabled persons.
• Firing or detonating a weapon, typically a nuclear device.
• In hacker jargon, the shutdown button or power switch on a computer, especially the red "emergency pull" switch on IBM mainframe operator consoles. The term has also sometimes been used for the power switch on IBM PCs.

On some mainframe designs, the emergency power-off switch would immediately physically disable the machine's power supply. Because the use of a Big Red Switch would bring down a computer in an uncontrolled fashion, getting the machine up and running again could be a nontrivial and time-consuming task. Therefore, particularly in the early mainframe computer era, people risked disciplinary action for activating the BRS of a production batch processing mainframe in a non-emergency situation (see molly-guard below).