In the novels of Arthur C. Clarke
, an artificially intelligent computer
on board the spacecraft Discovery
for the Jupiter
mission in 2001
. The term "HAL" stands for "Heuristic
ally programmed Algorithmic
. HAL, as he was commonly addressed, was first made operational at the HAL Plant in Urbana, Illinois
, on January 12, 1992. Among his instructors were Professor Langley and Dr. Chandra
The 9000 series of computers were considered incapable of error, and so HAL was put in charge of virtually every system on board the Discovery. He was even capable of carrying out the mission without human assistance, should the entire crew perish.
HAL fell victim to an induced psychosis (specifically, schizophrenia) during the Jupiter mission, due to his being ordered not to reveal the mission's true purpose to Mission Commander David Bowman or Astronaut Frank Poole. This conflicted with the basic purpose of HAL's design--the accurate processing of information without distortion or concealment--causing his circuits to become trapped in what was later diagnosed as a Hofstadter-Moebius loop. HAL first attempted to disrupt communications by making it appear that the AE-35 antenna-pointing control unit had malfunctioned, and killed Poole when he attempted to repair the unit during an EVA. When Bowman left the ship to rescue Poole, HAL sabotaged the ship's hibernation systems, killing the three crew members in suspended animation, and then refused to let Bowman's space pod reenter the ship. Bowman managed to gain access through the emergency airlock, and then disconnected HAL's higher functions.
HAL spent the next nine years "asleep," orbiting Jupiter's moon Io inside the derelict Discovery. He was successfully reactivated by Dr. Chandra and a team from the Russian spacecraft Leonov on their expedition to the Jovian system in 2010. HAL's memory of his psychotic break was successfully purged from his holographic memory systems, and he was later instrumental in relaying a warning message from Bowman (or, rather, Bowman's "spirit") to Dr. Heywood Floyd, giving the Leonov's crew a chance to escape before the cataclysmic explosion that turned Jupiter into Lucifer. HAL's physical components were destroyed with the rest of the Discovery in this explosion, but his "personality" was rescued by Bowman. Over the course of the next millennium, Bowman and HAL would spend most of their time inside the Monolith on Europa, attempting to map out its systems and decipher its secrets.
Over time, Bowman's and HAL's personalities gradually fused, leading Frank Poole (discovered by a comet-hunting expedition in 3001 and subsequently re-amimated) to dub the combined entity "Halman". When they discovered that the Monolith might be preparing to destroy Earth, the two entities volunteered to deliver dangerous software weapons into the Monolith's circuitry to destroy it before it could act. The plan was successful, and Bowman and HAL managed to copy their personalities to a petabyte memory tablet provided by Poole, but their "programs" had been corrupted by the software weapons. The tablet was brought to the Moon and sealed in a high-security vault on Mt. Pico, there to remain until the technology existed to make them safe.
* - Some people have pointed out that "HAL" is one letter ahead of "IBM," and have thought this to be a deliberate act. However, HAL's designers have repeatedly denied this, and have stated that they have the utmost respect for IBM. As it turns out, Big Blue didn't mind the association all that much.
Sources: Arthur C. Clarke, 2001: a space odyssey, 2010: odyssey two, 2061: odyssey three, 3001: The Final Odyssey; the films "2001: A Space Odyssey" and "2010"