/PROCESS=subprocess-name

    Specifies the name of the subprocess to be created. If you omit
    the /PROCESS qualifier, a unique process name is assigned with
    the same base name as the parent process and a unique number.

    The default subprocess name format is username_n. If you
    specify a process name that already exists, an error message is
    displayed. If the /LOG qualifier has been specified, the assigned
    name of the subprocess is displayed.

                                   NOTE

       Prior to OpenVMS Version 7.3-1, if no process name was
       supplied, the system constructed a name by appending _n to
       the user name, where n was the next available nonduplicate
       integer for any process currently in the system. For
       example, the first spawned process from user SYSTEM would
       be called SYSTEM_1, the second, SYSTEM_2, and so on. The
       next available number was chosen as soon as a gap was found.

       Starting with OpenVMS Alpha Version 7.3-1, a random number
       is chosen to append to the user name. In addition, starting
       with OpenVMS Version 8.3, the chosen number has, by default,
       a maximum value of 65535 instead of the former maximum value
       of 255. Therefore, the first processes that are spawned from
       user SYSTEM might be SYSTEM_7376, SYSTEM_9, SYSTEM_47124,
       and so on.

       Some applications might rely on the prior methods of
       assigning subprocess names. The DCL_CTLFLAGS system
       parameter allows you to configure the system as necessary.

       The rationale for changing from sequential to random
       number generation is that determining the next available
       open sequential number slot is very expensive in terms of
       performance. The mechanism attempts to create the process by
       incrementing names until it finds one that is unique. When
       several subprocesses already exist, the cost of creating the
       subprocess in the same OpenVMS group, the cost multiplies
       because process names must be unique throughout the group.

       The use of random number generation results in a very high
       probability of finding a unique name on the first try,
       because it is unlikely that the same number is already in
       use. This greatly reduces the cost of process creation, and
       applications that rely on spawned subprocesses might see a
       dramatic performance improvement as a result of this change.

       For more information, see the HP OpenVMS System Management
       Utilities Reference Manual for more information.