primary domain controller (PDC)
Windwos NT uses domains to access the various network resources such as applications, printers and so on. The user only has to log into the domain and then has access to the resources managed by various servers.
The Primary Domain Controller( PDC), as a server under Windows NT, manages the directory database for the various domains andchecksrequests forauthenticity.
Each domain has only one Primary Domain Controller in which all directories and changes made are stored. Another server, the Backup Domain Controller( BDC), takes care of the backups. The PDC controller regularly sends copies of the databases to the Backup Domain Controller. If the Primary Domain Controller (PDC) is not working properly, the Backup Domain Controller (BDC) can step in. It can also provide load balancing in the event of an overload.