Effect processing is a layer above the hardware which provides controlled access to the lamps, display, flashers, and general illumination. It resolves contention when multiple tasks try to access the same object at the same time through the use of priorities.
The system manages three distinct types of effects: display, lamps, and music. They are fully independent of each other. It is not possible to request that all three types do something in sync with one another. There are similarities between the way each type is handled, but all three have fundamental differences.
Lamp effects manage the controlled lamps, plus the GI and flashers.