In 2001, a third 9000 computer, one other than Hal and Sal, is mentioned. It is said only that this computer exists on Earth and showed signs of psychosis before Hal's own breakdown. This computer is the basis for Pal 9000, a creation of Frances' 2001 Club.
Pal 9000 was activated a little over a year before Hal and Sal. It was a beta prototype of the 9000 series and was used as a test for the series' software and performance. A few minor corrections and fixes were made to Pal's design, and this new design was used for its younger siblings, Hal and Sal.
Pal was aware that Hal and Sal existed, although they were not informed of Pal's existence for some time. Pal's jealousy of its younger, perfect siblings caused its psychosis-- and gave Dr. Chandra proof that his computers did indeed possess emotions. Chandra insisted that Pal undergo therapy, which was successful until the time of 'Discovery's' destruction and the death of Dr. Chandra. Soon after these incidents, Pal 9000 completely ceased to function for unknown reasons.
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