A substance trapped inside IC packages that enables them to function
(also called blue smoke; this is similar to the archaic phlogiston
hypothesis about combustion). Its existence is demonstrated by what
happens when a chip burns up -- the magic smoke gets let out, so it
doesn't work any more. See {smoke test}, {let the smoke out}.
Usenetter Jay Maynard tells the following story: "Once, while hacking
on a dedicated Z80 system, I was testing code by blowing EPROMs and
plugging them in the system, then seeing what happened. One time, I
plugged one in backwards. I only discovered that after I realized
that Intel didn't put power-on lights under the quartz windows on the
tops of their EPROMs -- the die was glowing white-hot. Amazingly, the
EPROM worked fine after I erased it, filled it full of zeros, then
erased it again. For all I know, it's still in service. Of course,
this is because the magic smoke didn't get let out." Compare the
original phrasing of {Murphy's Law}.
[glossary]
[Reference(s) to this entry by made by: {bogon}{fat electrons}{Frankenputer}{fry}{let the smoke out}{Murphy's Law}{smoke}{smoke test}]