Does PMIS(Project Management Information System) belong to EEFs?

Knowledge repositories are part of a PMIS, but they are not equal.

As Sergio points out, the term system is often misunderstood. It is really any group of items, whether electronic, mechanical, human, etc. that when organized together provide capabilities beyond what they can achieve separately.

OPAs can include many things like servers, paper libraries, policies, and procedures. If they do not interact, they are not part of the same system. Combining them together can create a system from the individual assets.

The system also includes the wiring or internet that allows them to communicate, the people reading a reference book and entering data, the management of all the information, and other items necessary for a system. You would not consider the connections between servers an OPA but they become part of the PMIS because it is required combine the data for a defined purpose.

@Youngho You will hate what I will write but here comes. First of all, if you are preparing the exam, remember that you have to answer what the PMI expect as an answer and not what you do or know in your daily life. Second, you will find inside the PMBOK that sometimes the PMIS is listed as an EEF and sometimes it is not. My recommendation in this case is: if you do not see the word PMIS then it is not the PMIS as stated in 4.3.2.2. For example, in the case you stated above, is not the same PMIS because the word PMIS and the word IT is not inside the statement you posted (in the case system is not used as software system).
The situation is wrost when you go to the glossary of terms where EEF is defined (this is the right definition) as "Conditions, not under the immediate control of the team, that influence, constrain,or direct the project, program, or portfolio." and you see the defintion of PMIS as "An information system consisting of the tools and techniques used to
gather, integrate, and disseminate the outputs of project management processes."
In both cases, those are definitions that are created without "software or IT" in mind.
So, by definition, PMIS must be an OPA (Organizational Process Asset).
I have debated a lot about this type of things from 2000 up to date, but I am one more inside a group of nominated SMEs. I have debated it because my main role as "author" is the creation of glossary of terms and as a "reviewer" is to review the whole document and aligned it to business analysis and agile). When I see this type of ambiguities it makes me nervous. Because of that, I have participated as SME in QA inside the exam questions creation group for PMP/PMI-PBA/PMI-ACP/Progran and Portfolio exams but the only thing I have got is that all exam questions for those exams becomes situational questions today then ambiguities into the answers have been avoided (as much as it can be). But, as you know, it is a voluntary work and final decisions are taking by the PMI directly. I made this final comment just trying to add some extra information. If you ask me about how to prepare the exam put your focus on answered tons of "exam like" questions (prehaps 4-5 the amount of exam questions quantity) and put your focus on understanding what is stated inside the Content Outline document you will find into the certification credential web site.

Such kind of you to give me a long reply!
I am very impressed. My 2019 will be happier thanks to you.

Thanks for your sincere advice and keep it in my mind!

Happy new year!