

What did the Big Red Button on IBM mainframes do? - mootothemax
http://geekhack.org/showthread.php?7185-What-did-the-Big-Red-Button-on-IBM-mainframes-do

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js2
According to "IBM System/360 Model 65 / Functional Characteristics"
(A22-6884-3):

 _EMERGENCY PULL Switch

Pulling this switch turns off all power beyond the power-entry terminal on
every unit that is part of the system or that can be switched onto the system;
therefore, the switch controls the system proper and all off-line and shared
control units and 110 devices.

The switch latches in the out position and can be restored to its normal
position by maintenance personnel only.

When the EMERGENCY PULL switch is in the out position, the POWER ON pushbutton
is ineffective._

\-- System Control Panel / Page 13

[http://www.bitsavers.org/pdf/ibm/360/funcChar/A22-6884-3_360...](http://www.bitsavers.org/pdf/ibm/360/funcChar/A22-6884-3_360-65_funcChar.pdf)

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jjm
I had a mainframe guy once tell me they had a red button that would call home
for tech support. Another big system he worked on would trigger a halon flood.
And on another it was just a off switch.

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ChuckMcM
My favorite of the 'do not push' buttons on the front of the mainframe was the
IMPL button, stood for 'Initial Micro Program Load' and it forced the loading
of the micro-code into the CPU.

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georgemcbay
Party button. If you pressed it, a disco ball would drop down and the latest
disco hits would play.

