Tech terms

PDC- Primary Domain Controller
DMZ- Demilitarized Zone (network term for public area in a router)

PDC stands for Parallel and Distributed Computing. It refers to a system that uses a multiple processor computer or several single processor computers ganged together to complete a single large task, broken into smaller sub-tasks.
The DMZ you speak of is very possibly also known as a Perimeter Network. The perimeter network has two purposes: First, to physically & logically separate an internal (or trusted) network from an external (or untrusted network), and second, to hide (or at least notadvertise) the internal network to the external/untrusted network.

Hope this has been helpful.