"Distributed" is a very general term. Which interpretation of it are you referring to?
If talk about "data sharing", there is also "non data sharing". The difference is if different database partitions/members have access to the data of other partitions/members. If the access is possible, you have "data sharing". Otherwise, it is "non data sharing". The DPF feature of DB2 LUW is non data sharing; DB2 z/OS is data sharing.