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ERUN command

The ERUN command runs a system program without disturbing the  program
already in memory by placing the program in an ephemeral fork.


     @ERUN (PROGRAM) filespec


     filespec       is the file specification of a system program.
                         Default dev:<directory> - SYS:

                         Default .typ - .EXE


     Characteristics of an Ephemeral Fork

          The ERUN command runs a program in  an  ephemeral  fork.   A
          program  that  runs  in  an ephemeral fork acts like an EXEC
          command (excluding those EXEC commands that run programs  or
          otherwise affect memory).  Ephemeral forks and EXEC commands
          share these characteristics:

           o  They do not affect programs in memory.  For example,  if
              you  exit a program and issue a SYSTAT command, or run a
              program in an ephemeral fork, neither  the  command  nor
              the ephemeral fork will disturb the program in memory.

              A program that runs ephemerally is always  placed  in  a
              new fork.

           o  They  disappear  when  interrupted  or  when  processing
              completes.   For  example,  if  you  stop execution of a
              SYSTAT command or an ephemeral fork with CTRL/C, neither
              the command nor the ephemeral fork can be continued.

              Whenever you stop or exit an ephemeral fork, the fork is
              automatically reset (cleared from memory).

          Good candidates for ephemeral forks are  programs  that  may
          have short execution times and simply display information in
          a manner similar to the INFORMATION and SYSTAT commands.

Related Commands

     INFORMATION LOGICAL-NAMES     for  examining  the  definition  of

     R                             for  running  executable   programs
                                   stored on SYS:

     RUN                           for   running    executable    user

     SET FILE EPHEMERAL            for  giving  a  file  a   permanent
                                   ephemeral attribute

     SET PROGRAM EPHEMERAL         for  running  a   program   in   an
                                   ephemeral fork


     1.  Display the status of the fork in memory with the INFORMATION
         FORK-STATUS  command.   Then,  run  a program in an ephemeral
         fork in order to preserve the state  of  your  job's  memory.
         Redisplay the fork status and note that the ephemeral program
         has been reset and has not replaced the original fork.

               => EMACS (1): HALT AT 50340, 0:00:03.6
              @ERUN TERMSTAT

              Lab  Terminals in use  Free terminals
              ---  ----------------  --------------
              A          17               0
              B          12               4

               => EMACS (1): HALT at 50340, 0:00:03.6