Big Red Switch

[IBM] The power switch on a computer, esp. the `Emergency Pull' switch on an IBM {mainframe} or the power switch on an IBM PC where it really is large and red. "This !@%$% {bitty box} is hung again; time to hit the Big Red Switch." Sources at IBM report that, in tune with the company's passion for {TLA}s, this is often abbreviated as BRS (this has also become established on FidoNet and in the PC {clone} world). It is alleged that the emergency pull switch on an IBM 360/91 actually fired a non-conducting bolt into the main power feed; the BRSes on more recent mainframes physically drop a block into place so that they can't be pushed back in. People get fired for pulling them, especially inappropriately (see also {molly-guard}). Compare {power cycle}, {three-finger salute}; see also {scram switch}.

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