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drop-ins n. [probably by analogy with drop-outs] Spurious characters appearing on a terminal or console as a result of line noise or a system malfunction of some sort. Esp. used when these are interspersed with one's own typed input. Compare drop-outs, sense 2.
drop-outs n. 1. A variety of power glitch (see glitch); momentary 0 voltage on the electrical mains. 2. Missing characters in typed input due to software malfunction or system saturation (one cause of such behavior under Unix when a bad connection to a modem swamps the processor with spurious character interrupts; see screaming tty). 3. Mental glitches; used as a way of describing those occasions when the mind just seems to shut down for a couple of beats. See glitch, fried.
drugged adj. (also on drugs) 1. Conspicuously stupid, heading toward brain-damaged. Often accompanied by a pantomime of toking a joint. 2. Of hardware, very slow relative to normal performance.
drum adj, n. Ancient techspeak term referring to slow, cylindrical magnetic media that were once state-of-the-art storage devices. Under BSD Unix the disk partition used for swapping is still called /dev/drum; this has led to considerable humor and not a few straight-faced but utterly bogus 'explanations' getting foisted on newbies. See also "The Story of Mel, a Real Programmer" in Appendix A.
drunk mouse syndrome n. (also mouse on drugs) A malady exhibited by the mouse pointing device of some computers. The typical symptom is for the mouse cursor on the screen to move in random directions and not in sync with the motion of the actual mouse. Can usually be corrected by unplugging the mouse and plugging it back again. Another recommended fix for optical mice is to rotate your mouse pad 90 degrees.
At Xerox PARC in the 1970s, most people kept a can of copier cleaner (isopropyl alcohol) at their desks. When the steel ball on the mouse had picked up enough cruft to be unreliable, the mouse was doused in cleaner, which restored it for a while. However, this operation left a fine residue that accelerated the accumulation of cruft, so the dousings became more and more frequent. Finally, the mouse was declared 'alcoholic' and sent to the clinic to be dried out in a CFC ultrasonic bath.
Duff's device n. The most dramatic use yet seen of fall through in C, invented by Tom Duff when he was at Lucasfilm. Trying to bum all the instructions he could out of an inner loop that copied data serially onto an output port, he decided to unroll it. He then realized that the unrolled

 
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