can you please tell me, if my ES is an RS/6000 with an Oracle database can my central objects reside on the ES in Oracle or do they "have to reside" in an Oracle database on the DS?
Its far easier/cheaper to keep your central objects in the ES database.
the default reccommendation from JDE when we implemented was to put a separate central objects database on the DS but it made no sense to do that so we didn't. Never regretted it either.