The sharpest memory I have of this one is that it was unusually dense reading. Much more difficult going than most of the sci-fi stuff I'd read by that time (I was 10 or 11, I think).
What I remember in terms of plot is that there is a starship, sent either to explore, or colonize, a distant star system. I don't remember the names of any of the characters, but I think maybe they discover they are clones? In any case, something happens to the computer system that the onboard AI becomes sentient and develops a measure of omniscience and omnipotence. It effectively becomes a god of sorts.
The next part I can remember, and I'm not sure this is the same book or not, is that the ship has forcibly settled the crew on a hostile planet. All sorts of nasty indigenous life forms live here, and guards are post on the wall outside the settlement to destroy them as they try to enter. I remember there is a female character standing watch, and she goes over the bestiary in her mind. One particularly nasty creature paralyzes you, and then burrows up your spine into your brain (or something like that) if it gets a hold of you.
That's all I can recall. Not a lot of detail, unfortunately, but I'm having a tough time remembering much about this one. I never finished the book(s), as they were mostly "over my head" at that age.