burn-in period

1. A factory test designed to catch systems with {marginal} components before they get out the door; the theory is that burn-in will protect customers by outwaiting the steepest part of the {bathtub curve} (see {infant mortality}).
2. A period of indeterminate length in which a person using a computer is so intensely involved in his project that he forgets basic needs such as food, drink, sleep, etc. Warning: Excessive burn-in can lead to burn-out. See {hack mode}, {larval stage}.

   Historical note: the origin of "burn-in" (sense 1) is apparently the practice of setting a new-model airplane's brakes on fire, then extinguishing the fire, in order to make them hold better. This was done on the first version of the U.S. spy-plane, the U-2.

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