Of course I understand what a daemon is in this context. It is a program that runs continuously in the background on a system -- generally not visible to the user -- and handles certain actions generated by users or other programs. Other words commonly applied to "daemon" programs include "server", "service", or (way back in the old days of DOS) "TSRs (Terminate and Stay-Resident applications)".
But the word itself has puzzled me, particularly when less-tech-savvy associates have asked me, "Why do they call it a 'demon'? Isn't a demon basically an evil spirit? What's so bad or scary about these 'demons'?"
Well, as usual I turned to Wikipedia for the answer. I'll let you do the searching yourself if you're curious about the sources, but basically it comes down to this: Originally a daemon (being a more ancient spelling of the word "demon") actually wasn't an evil or malignant spirit at all. It comes from a greek term for "supernatural beings between mortals and gods, such as inferior divinities and ghosts of dead heroes". In many cases it even referred to benevolent spirits who involved themselves in the welfare of individual humans -- like our modern concept of a "guardian angel".
But the term as used in modern IT lingo, to refer to these "hidden" server-type programs, was coined by a computing team at MIT in the 60s, and they actually took it from Maxwell's Daemon -- a thought experiment in which a "demon" (that is, a hidden influence or a mediating force) is able to violate the Second Law of Thermodynamics.
In other words, the term "daemon" has nothing to do with an evil spirit or a malevolent influence. Rather, it's a constant, yet hidden, mediating influence that intercedes to change the behavior of a system.
So now when people ask me, "Why is it called a daemon?" I can tell them, "It's a Ghost in the Machine."
Maybe that will shut them up. On the other hand, maybe they'll just be too afraid to use their computer. Either way -- problem solved.
No comments:
Post a Comment