Use the multiprocess configuration to debug a program that
    normally runs in more than one process. This configuration is
    achieved when DBG$PROCESS has the definition MULTIPROCESS, and it
    enables you to interact with several processes from one debugging
    session.

    Use the following command to establish a multiprocess debugging
    configuration:

    $ DEFINE/JOB DBG$PROCESS MULTIPROCESS

    As shown in this example, when defining DBG$PROCESS for a
    multiprocess configuration, use a job logical definition so that
    the definition applies to all processes in that job. An image
    can be connected to (and controlled by) an existing multiprocess
    debugging session only if the process running the image is in the
    same job as the process running the debugging session.

    Although all processes of a multiprocess configuration must
    be in the same job tree, they do not have to be related in a
    particular process/subprocess hierachy. Moreover, the program
    images running in separate processes do not have to communicate
    with each other.