What is the X in X-mas?
operating system, exception
The Amiga equivalent of Unix's panic (sometimes just called a "guru" or "guru event"). When the system crashes, a cryptic message of the form "GURU MEDITATION #XXXXXXXX.YYYYYYYY" may appear, indicating what the problem was. An Amiga guru can figure things out from the numbers.
In the earliest days of the Amiga, there was a device called a "Joyboard" which was basically a plastic board built onto a joystick-like device; it was sold with a skiing game cartridge for the Atari game machine. It is said that whenever the prototype OS crashed, the system programmer responsible would concentrate on a solution while sitting cross-legged, balanced on a Joyboard, resembling a meditating guru. Sadly, the joke was removed in AmigaOS 2.04.
The Jargon File claimed that a guru event had to be followed by a Vulcan nerve pinch but, according to a correspondent, a mouse click was enough to start a reboot.