In honor of what would have been director Stanley Kubrick's 83rd birthday on this date, we reveal what might have been the real reason HAL 9000 sang "Daisy Bell" in 2001: A Space Odyssey.

Remember how in Kubrick's 1968 visionary science fiction masterpiece, astronaut Dave Bowman (Keir Dullea) is forced to shut the supercomputer HAL 9000 down after it malfunctions and kills the rest of the crew on their Jupiter-bound spacecraft? Well, as Bowman unplugs HAL's connections one by one, the machine sort of has a flashback to its very first day of operation, when it demonstrated its abilities by singing a song.

The song? "Daisy Bell," written in 1892 by Harry Dacre. But where did Kubrick get the idea to use that particular tune?

It turns out that in 1961, the IBM 7094, among the earliest and largest mainframe machines developed by the computing giant, became the first computer to sing, and the tune it warbled was—you guessed it—"Daisy Bell." The vocals were programmed by John Kelly and Carol Lockbaum, while the musical accompaniment was programmed by Max Mathews. It seems certain that Kubrick used this as the inspiration for HAL's signoff in his movie.

A recording of the IBM 7094's rendition is below. We think HAL's got a smoother voice, but the 7094's performance was more historic by far.

(via Roger Ebert's Journal)