In this article, the title question is really only the jumping-off point for an extended discourse, but insofar as it has been raised...
The story would have been uninteresting (or at least very different) if HAL had been acting on direct orders, and Clarke does not seem to have in mind that the mission was deliberately crafted with the intent that HAL would take homicidal action on its own initiative. Instead, HAL, in an unanticipated divergence, is confused by the apparent inconsistencies in the mission plan resulting from its goals being concealed, and, "like a neurotic", unable to recognize its own state, concludes that the astronauts must be killed for the greater good of the mission.
If, by "following orders", you are saying that HAL is a deterministic machine, then we are getting into the issue of free will. For what it is worth, Dennett is a 'compatibilist', maintaining that free will, in some sense, is compatible with physical determinism, but I don't know enough about that viewpoint to comment further. "Free will" is not explicitly mentioned anywhere in the article, I would guess because it is too deep a rabbit-hole for an article of this length and scope.
The story would have been uninteresting (or at least very different) if HAL had been acting on direct orders, and Clarke does not seem to have in mind that the mission was deliberately crafted with the intent that HAL would take homicidal action on its own initiative. Instead, HAL, in an unanticipated divergence, is confused by the apparent inconsistencies in the mission plan resulting from its goals being concealed, and, "like a neurotic", unable to recognize its own state, concludes that the astronauts must be killed for the greater good of the mission.
If, by "following orders", you are saying that HAL is a deterministic machine, then we are getting into the issue of free will. For what it is worth, Dennett is a 'compatibilist', maintaining that free will, in some sense, is compatible with physical determinism, but I don't know enough about that viewpoint to comment further. "Free will" is not explicitly mentioned anywhere in the article, I would guess because it is too deep a rabbit-hole for an article of this length and scope.