[IBM] The power switch on a computer, especially 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 TLAs, this is often abbreviated as

"BRS" (this has also become established on FidoNet and in the

IBM PC 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 powercycle, three-finger salute, 120 reset; see also scramswitch.