Connecting Client and Server

My next assignment will have me working with a huge IBM DB2 database on the z/OS. So I have been trying to learn more about DB2. I installed a copy of DB2 on Windows XP. But now I am trying to get a handle on client/server connectivity with DB2.

So far the book "Understanding DB2" has helped me with a number of DB2 topics. However it only seems to confuse me when trying to explain connectivity configuration. The book mentions the catalog command. However I am not sure what this command is supposed to do. I guess it might mean show me the contents (of a database). Or maybe it shows me the databases available. The book seems to indicate that catalog is more of an active command. But I am still clueless.

Luckily I have a local DB2 database on Windows XP. So things should be simple here. But I want to understand. It might be time to get another book. Tried looking up catalog on the web but that was fruitless. I started feeling better when the book mentioned using TCP/IP to connect to a server. But in the same paragraph it was mentioning APPC as if I should know what that means. Wikipedia helped out in explaining that this stood for IBM's Advanced Program to Program Communication, and that this was a part of SNA. I just hope the next project uses TCP/IP.

On a final note, I would say that the whole idea of directories was confusing as well. There seems to be a whole hierarchy of directories that work in DB2. Again maybe it is that my book is weak on this topic. But I just don't get it. Sometimes it sucks to be the new guy in a complex technology such as DB2.