Mission (payload) data
SC (operational) data
Satellite may live much longer than you anticipate (e.g. QuakeSat) or primary mission may be short-lived (e.g. GeneSat). If operation is autonomous / scriptable, you may get a lot more data than you bargained for.
Uploadable or alternate stored code enables multiple, different missions to be performed after the primary mission is over (e.g. GeneSat and injecting faults to see if GS software can detect them heuristically)