Who created $foo $bar?

During my recent programming course on PHP, we had to use variables to store data. The content or use of those variables wasn't significant to the thing we had to learn, so as is common in coding circles we used variables $foo and $var. I wonder who first used the variables $foo $bar?

In terms of the word "fubar" or "foobar", I first heard it mentioned in the film "Saving Private Ryan", and a quick google search lead me to this page that has some interesting notes/theories/ideas? on the origin of the term.