Use the default configuration to debug a program that normally
    runs (without the debugger) in only one process. This
    configuration is achieved when DBG$PROCESS is either undefined
    or has the definition DEFAULT.

    In the following example, the output of the SHOW LOGICAL command
    indicates that a default debugging configuration is in effect:

    $ SHOW LOGICAL DBG$PROCESS
    %SHOW-S-NOTRAN, no translation for logical name DBG$PROCESS

    If DBG$PROCESS has the value MULTIPROCESS, and you want to debug
    a program that runs in only one process, enter the following
    command:

    $ DEFINE DBG$PROCESS DEFAULT