The Operations Master roles ( AKA FSMO pronounced FIZZMOE) are, by default, assigned to the first DC installed in an Active Directory environment.
Schema Master The Schema is the field structure of the AD Database in this context – The Schema master maintains that schema, in the case of Schema modifications – such as intalling Exchange, running adprep.exe/forestprep or a third party app that hooks itself into Active Directory (Cognos for example.) This role is unique to the forest. To view the Schema Master, you need to register the schmmgmt.dll file, and then add Schema Management to a mmc console. You can now right click and view the owner of this role (and change it if so desired.)
Domain Naming Operations Master – Makes certain that each domain object has a unique name. This role is unique to the forest. To see and or transfer this role, use Active Directory Domains and Trusts, select a domain controller, and choose Operations Master.
Infrastructure Master Maintains the security cross domains, such as checking for memberships in Universal Groups in other domains. This role is unique to the domain. If you want to see which domain controller has this role, open Active Directory Users and Computers, choose a domain, right click and choose Operations Masters.
RID Master Makes sure that each object has a unique relative identifie, and processes RID requests from all domain controllers in a domain. This role is unique to the domain. If you want to see which domain controller has this role, open Active Directory Users and Computers, choose a domain, right click and choose Operations Masters.
PDC Emulator Backwards Compatibility with NT4 BDCs, but also needed for the W32 time service. This role is unique to the domain. If you want to see which domain controller has this role, open Active Directory Users and Computers, choose a domain, right click and choose Operations Masters.
The Global Catalog is not a FSMO, but is also noteworthy here. To find and set a GC server, go to Active Directory Sites and Services, drill down to the server of interest, click on that server’s NTDS settings and tick the Global Catalog box.