Programmers - why foo?

I’m a beginning comp sci. student in college, and I keep running into “foo” being used as a variable or a value in various computer programs.

Everyone from my boss at work to my professor use it, and yet no one can seem to explain its origin or meaning. Anyone know?

It’s from an old comic strip. Behold, the miracle of the jargon file!

http://www.tuxedo.org/~esr/jargon/html/entry/foo.html