Detached Process

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A detached process is a type of process that executes independently of its parent process, sometimes referred to as a "daemon". Interactive and batch processes are therefore detached. Detached processes are started by JOB_CONTROL or users with the DETACH privilege by running images with the RUN/DETACHED or RUN/UIC command and may take their input from a terminal or a command file.

RUN/DETACHED creates a detached process with the same UIC as the one executing the command. RUN/UIC creates a detached process with any UIC.

Process characteristics

Characteristics of the detached process are determined by the user's SYSUAF values as well as the qualifiers specified on the RUN and SUBMIT commands.


By default, resource quotas for the detached process are limited by the quotas of the creator process (maximum) and the system parameters PQL_M* (minimum). The DETACH or CMKRNL privilege allows you to specify any quotas for the detached process that exceed the normal range. Unless you have the DETACH or CMKRNL privilege, the maximum number of detached processes that you can create is limited to the quota defined by MAX_DETACH in your SYSUAF.

Jobwide logical name table

/JOB_TABLE_QUOTA allows you to specify a quota for a detached process's jobwide logical name table.


/ON specifies an OpenVMS Cluster node on which a detached process is to be created. Quotas are determined by comparing the values.

Running Command Procedures as a Detached Process

You can run command procedures as a detached but not batch process as follows:

RUN SYS$SYSTEM:LOGINOUT.EXE /UIC=uic /INPUT=command_procedure /OUTPUT=log_file /ERROR=error_file

If you want to run it under your username, use /DETACHED instead of /UIC.