Complex sentence: The National Security Council ordered HAL to conceal from Discoverys crew the fact that the mission was about the Monolith; this conflicted with HAL's basic programming of open, accurate processing of information, causing him to suffer a paranoid mental breakdown.
Split into simpler sentences: The National Security Council ordered HAL to conceal from Discoverys crew the fact that the mission was about the Monolith. This conflicted with HAL's basic programming of open, accurate processing of information, causing him to suffer a paranoid mental breakdown.