Wholesale Heretic by David Drake

[Baen] David Drake’s legendary Raj Whitehall/The General series, stunningly reborn! In a world of muskets, bows and arrows, and reptile riding nomads, a young warrior fights against a totalitarian computer devoted to stasis. ABEL DASHIAN'S WORLD DOESN'T NEED A HERO Duisberg is one of thousands of planets plunged into darkness and chaos by the collapse of the galactic republic, but where other worlds have begun to rebuild a star-travelling culture, Duisberg remains in an uneasy balance between mud-brick civilization and bloodthirsty barbarism. The people of Duisberg have a god: Zentrum, a supercomputer from the ancient past. Zentrum has decided avoid another collapse by preventing civilization from rising from where it is. And because even a supercomputer and the powerful religion which it founded cannot block all progress, Zentrum has another tool: every few centuries the barbarians sweep in from the desert, slaughtering the educated classes and cowing the peasa