The JES3 Exit IATUX30 enables Control‑D (the Control‑D monitors and the Printers Control monitors CTDPRINT) to issue subsystem requests.

JES3 has a special security exit for controlling subsystem requests. This exit controls two types of subsystem requests:

• Job status subsystem requests

  Control‑D searches the jobs to be decollated from the spool using the job status subsystem request. JES3 Exit IATUX30 can prevent Control‑D from receiving the status of the job. This causes report decollating missions to remain in WAITING FOR JOB status even if the job output for which the missions are waiting is in the output queue.

• Sysout read subsystem requests

  Control‑D reads the sysout from the spool using the regular MVS subsystem interface. JES3 Exit IATUX30 can prevent the Control‑D monitor from reading the output of jobs from the spool. This causes the following problems:

  • Control‑D does not find any output for the job on spool although output seems to exist.
  • The Control‑D Printers Control monitor does not pause between "chunks" of output that are directed to spool. You can see several outputs for the same printer on the spool.

If JES3 Exit IATUX30 is used to check and prevent subsystem requests by unauthorized users, it must be modified to allow Control‑D to issue subsystem requests for all the jobs. The recommended method is to place a check at the beginning of the exit for the started task names of the Control‑D monitors and the Control‑D Printers Control monitors, and to bypass all other checking when the request originates from them.