The system provides two types of categories:
Each component maintains a bitmap for basic category membership. The default eight categories consume one byte and each increment of eight categories you add consumes an additional byte (1–8, 9–16, 17–24, and so on) in the component record.
All components must be assigned to at least one basic category, either an explicit assignment, or an inherited assignment from a parent component. Beyond this assignment, which type of category to use depends on your needs. You may use explicit and inherited categories at the same time.