Using the IMS CHKPID parameter
In the JCL to execute an IMS application program, AR/CTL supports use of the CHKPID parameter (the eighth positional parameter of a DLI EXEC statement, or the ninth positional parameter of a BMP EXEC statement). AR/CTL supports all IMS supported keywords and values in the CHKPID parameter. AR/CTL also supports AR/CTL-defined keywords, which allow you to cold-start the job step and, as an option, to suppress checkpoint messages. The AR/CTL-defined keywords are valid only when AR/CTL is present during execution.
The following table shows CHKPID parameter keywords that control message suppression, cold start, or both. The message suppression keywords do not affect the restart status of the job step.
CHKPID parameter keywords
Keyword | Definition | Supported by IMS without AR/CTL |
|---|---|---|
NOMSGS | Do not issue any checkpoint messages. | yes |
NOMSG540 | Do not issue any DFS540I messages. | yes |
NOMSG542 | Do not issue any DFS542I messages. | yes |
NOMSG681 | Do not issue any DFS681I messages. | yes |
NO681542 | Do not issue any DFS681I or DFS542I messages. | yes |
COLD | Cold-start the job step. | no |
COLDMSGS | Cold-start the job step, and do not issue any checkpoint messages. | no |
COLDMSG540 | Cold-start the job step, and do not issue any DFS540I messages. | no |
COLDMSG542 | Cold-start the job step, and do not issue any DFS542I messages. | no |
COLDMSG681 | Cold-start the job step, and do not issue any DFS681I messages. | no |
COLD681542 | Cold-start the job step, and do not issue any DFS681I or DFS540I messages. | no |
The following shows how AR/CTL handles other keywords and values in the CHKPID parameter:
- If the CHKPID parameter contains an 8-character checkpoint ID and the identified checkpoint record is in the restart data set, AR/CTL performs the restart. If this record is not flagged as valid for restart, AR/CTL issues an abnormal termination for the job step.
- If the CHKPID parameter contains an 8-character checkpoint ID and the identified checkpoint record is not in the restart data set, AR/CTL issues an abnormal termination for the job step.
- If the CHKPID parameter contains a time stamp and the application program does not use any AR/CTL repositioning services, AR/CTL passes control to IMS and IMS performs the restart. The Reattach Application Program option is set to N.
- If the CHKPID parameter contains a time stamp and the application program uses any AR/CTL repositioning services, AR/CTL issues an abnormal termination for the job step.
- If the CHKPID parameter contains the LAST keyword and the application program uses any AR/CTL repositioning services, AR/CTL ignores the keyword and performs the restart.
- If the CHKPID parameter contains the LAST keyword, the application program does not use any AR/CTL repositioning services, and the program is executing in a DLI batch environment, AR/CTL ignores the keyword and performs the restart.
- If the CHKPID parameter contains the LAST keyword, the application program does not use any AR/CTL repositioning services, and the program is executing in a BMP batch environment, AR/CTL passes control to IMS and IMS performs the restart.