CK - 2017-05-05

Hi,
I'm interesting in pcd but using it first time.
I would like to ask some fundamental questions.
By the description, the feature of pcd seems like systemd + process monitor. Is it right about my understanding?
Does the pcd process be launch by systemd or not?
If only by case of system service initial, what service should be in systemd, what for pcd?
Thanks.

C.K