Big Red Switch
Encyclopedia : B : BI : BIG : Big Red Switch
Big Red Switch (BRS) is a hacker term for 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: "This !@%$% is hung again; time to hit the Big Red Switch.") It is alleged that the emergency pull switch on IBM 360 Model 91s 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.
Because the use of a Big Red Switch will bring down a computer in an "uncontrolled fashion" (since the operating system won't be able to flush the file system buffers and generally tidy up the computer's memory contents before power-off), getting the machine up and running again can be a nontrivial and cumbersome task taking quite some time. Therefore, particularly in the early mainframe computer era, people risked getting fired for pulling/pushing the BRS of a production batch processing mainframe if this wasn't absolutely necessary as part of an emergency action (see ).
See also
- Scram switch
- Three-finger salute
- 120 reset
- This article was originally based on material from the Free On-line Dictionary of Computing, which is [Foldoc licenselicensed] under the GFDL.
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