The title is a bit misleading; the computer isn't really the focus of the story; it's certainly not the threat the episode synopsis implies. And there isn't any kind of "human computer", like some super-brain person or anything.
But the episode is a different kind of story than those I've seen so far. It's mainly David Hedison alone -- or almost alone -- on the Sea View, fighting his paranoia and perhaps something more tangible. Moody tone; lots of shadows; long, long passages with no dialogue. Toward the end there's a striking scene where Hedison has to swim through a narrow, flooded conduit.
Hedison, according to IMDB, is still going strong, appearing in soaps and movies as recently as 2005.