Normal PSF recovery

Under JES, PSF monitors pages as they pass through the printer, and records checkpoint data in local storage. If a recoverable I/O error interrupts the processing of a data set, PSF uses this checkpoint data to resume processing at the point of interruption, with minimal operator intervention. This page-level recovery prevents duplicate or missing pages (provided that the operator follows documented operational procedures) because PSF knows the last successfully printed page and can restart the print job from that page if an error is encountered.

PSF also uses the JES checkpoint function to write the checkpoint data to the JES checkpoint data set at the intervals specified in the JES initialization statements. The system operator can enter JES commands to restart printing from the JES checkpoint data set.

Checkpoint intervals can be specified in places that PSF uses in the following order:

1. CKPTPAGE or CKPTSEC parameter in the user JCL.

   If both of these parameters are specified in the user JCL, JES2 or JES3 determines which is used. See the z/OS MVS JCL Reference for more information.

2. Applicable JES initialization parameters:
   • JES2 initialization CKPTPAGE, CKPTSEC, and CKPTMODE parameters. See Parameters for the JES2 initialization statement.
   • JES3 initialization CKPNTPG and CKPNTSEC parameters. See Parameters for the JES3 initialization statement.

For some errors, sense-byte information might be provided to the operator. Some of the printers PSF supports report 24 bytes of sense information to identify the cause of every unit-check error; other printers report fewer sense bytes. Sense-byte 2 contains error-recovery action codes for conditions sensed by the printer. For more detailed sense-byte information, see the publications for your printer.

If PSF is running in direct-printing mode, error conditions that cause data loss can also cause an abend.