Specifying printer checkpoints

Use the CKPTPAGE or CKPTSEC parameter on the OUTPUT statement (see CKPTPAGE and CKPTSEC) to specify when you want the checkpoint data recorded.

Examples:

This example specifies that the printer checkpoint is at 20 pages. For printing a large data set, see Considerations.
```
//OUT2 OUTPUT CKPTPAGE=20
//DD2 DD SYSOUT=class,OUTPUT=(*.OUT2)
```
This example specifies that the printer checkpoint is at 120 seconds:
```
//OUT1 OUTPUT CKPTSEC=120
//DD1 DD SYSOUT=class,OUTPUT=(*.OUT1)
```

Notes:

CKPTPAGE and CKPTSEC do not apply to direct-printing mode.
Do not specify both CKPTPAGE and CKPTSEC. If you do, the parameter used depends on the defaults for your installation. See the JCL reference publication for your operating system.
If you specify neither the CKPTPAGE nor the CKPTSEC parameter, JES uses the system default. If you are using the "Page-Printer Defaults" form, the default checkpoint values for the system are shown. See Page-printer defaults form for a blank form. If no system default is given, PSF does not record checkpoints.
PSF takes internal checkpoints at the specified intervals and transmits a request to JES to record the checkpoint data it gathers. The operator can use these internal checkpoints when issuing commands to the printer.
A smaller checkpoint interval causes more internal checkpoints to be taken during the processing of a data set. This enables PSF to find the target of the operator command with less processing overhead. However, too small a checkpoint interval can cause excessive use of virtual storage. Be aware of the need to balance between the overhead for processing operator commands and the use of virtual storage.
If a system failure occurs, PSF does not guarantee that checkpoint information is used to restart the data set.
When the PSF attachment is Systems Network Architecture (SNA) or TCP/IP, the checkpoint interval specifies the maximum number of pages or amount of time after which PSF requests an acknowledgment from the printer. If acknowledgments are requested too often, printing performance can be adversely affected.
When the PSF attachment is SNA or TCP/IP and after a session is ended, PSF restarts printing from the most recent checkpoint. Therefore, more frequent checkpoints can reduce the number of pages reprinted after restart.