Having a hard time clearing a issue, that i was hoping someone could help.

PMIS - Project Management Information System 

Includes:

Configuration Management System within Perform integrated Change Control Process Group.

and included in the CMS

Change Control System & Change Control Board.

All of these systems are part of EEF (Enterprise Environmental Factors)

Here is my confusion, I came across a prep test question that was asking about the Direct and Manage Project Execution Group and referred to a Configuration Management Knowledge Base and being part of the OPA (Organizational Process Assets)

Is the Configuration Management Knowledge Base different from the Configuration Management System?

and if they are different why is a knowledge base part of OPA?

This one is killing me, thanks for any help