Hal Timeline and Summary

Computer technology through the 1980s and 1990s (of the novel) figured out how to grow computer brains similar to human ones.
Hal became operational in 1997.
He was tasked with running Discovery, and secretly told that the mission was to find aliens.
He wasn't supposed to tell the non-hibernating crew members.
Keeping a secret went against his basically truthful nature, and he went insane, killing all crew members except for David Bowman.
David Bowman disconnects him.
Goodbye, Hal.