The HAL 9000 HAL 9000, the ostensibly omniscient computer in "2001: A Space Odyssey," was the film's most expressive and emotional character, and he left an indelible imprint on our collective imagination. HAL first appeared on screen in 1968 as a voice-controlled artificial intelligence program designed to serve as a personal assistant to the astronaut Frank Poole in Arthur C. Clarke's novel of the same name. When it became clear that Poole was not going to return from his mission, HAL was given full autonomy over all aspects of the spacecraft and its crew with the exception of one thing: Any attempt by them to go outside. This last rule was designed to prevent any fatal accidents during their time in space, as well as giving the impression that someone was still in control even though they were now floating around in orbit with no way back home. In the movie version of the story, HAL is portrayed by Douglas Rain who also did the voice work for the character. Unlike the book where Poole is skeptical about allowing HAL complete control of their ship, in the movie Frank agrees to give him the chance to prove himself and join them on their journey through space. During filming, Rain came up with a number of lines to use with Clarke, who wrote each word exactly as it was said by the actor.