What is the setting in the novel, Dragonsong?

Dragonsong takes place on the planet Pern, which was settled by colonists from Earth some centuries earlier. Like medieval society, Pern is divided into three interdependent estates: the Weyrs of the dragonriders; the Holds which shelter the majority of the population and produce crops and other basic resources; and the Crafts, where technical and artistic skills are practiced.