Q. Illustration of a demon program?

When the PVM initialize it inspects the virtual machine in that it's to operate and creates a process known as PVM demon or simply pvmd on every machine. An Illustration of a demon program is the mail program which runs in the background and handles all incoming and outgoing E-mail on a computer, pvmd offers inter-host point of contact, authenticates task and executes processes on machines. It as well as offers the fault detection, routes messages not intended for or from its host, sends messages from its application to destination, receives messages from other pvmd's and buffers it till destination application is able to handle it.