Install jobs can be run in local batch mode or through the CV. It may be unclear which way these should be run.
For an IDMS install, either base or upgrade, whether each job step is run under the CV or not will be controlled by the presence or absence of a SYSCTL DD statement in the job step. If a SYSCTL is present, the job will run under the CV's control. If it is absent, the job will run in local mode. The advantage of running under the CV is that if errors occur, those will be rolled out. If the jobs are run in local mode then if an abend occurs, the dictionaries must be restored manually from backups taken either before the install process was begun, or at intermediate stages within the install.
The inclusion or exclusion of the SYSCTL DD statement in the install job steps is controlled by the GJCVMODE parameter in the VARBLIST. The default for this is NO, indicating that the SYSCTL DD statement will not be included in the generated JCL, and CV mode will not be used. If you want to run the install jobs through the CV in order to take advantage of automated recovery in case of an error, then GJCVMODE=YES should be specified in the VARBLIST.
Some sites prefer to run their dictionary update jobs in local mode; to do that backups should be taken of the dictionaries and GJCVMODE=NO should be specified in the VARBLIST. Then the CV will need to be brought down, or all of the dictionary areas to be updated varied offline, while the install jobs are running.
Sysgen changes made by the upgrade install are made to System 99 and 90. You must then copy Tasks and Programs from system 99 to your actual system before generating it and bringing up the system under the new release.