PL/I

The PL/I user can use automatic and deferred step restart and can use COMMAND PQUIT to take checkpoints and get automatic and deferred checkpoint restarts. To cause a checkpoint entry to be written and request an automatic checkpoint/restart, the user codes CALL PLICKPT.

Each checkpoint entry in the checkpoint data set is identified by a system-generated checkid. A system message (including the checkid) at the console notifies the operator that a checkpoint entry is written.

The organization of the checkpoint data set is always physical sequential, and the data set may be written on magnetic tape or a direct access volume. Partitioned organization cannot be used.

A DD statement must be present in the job stream to define the checkpoint data set. The DISP parameter in this DD statement is used to specify whether single or multiple checkpoint entries are to be written. DISP=(NEW,KEEP) specifies a single checkpoint entry; DISP=(MOD,KEEP) specifies multiple checkpoint entries.

If CALL PLIREST is used in PL/I programs, the SCHEDxx PARMLIB member must specify 4092 as an eligible user completion code. For more information see Specification of Codes Eligible for Restart.