Coding the checkpoint I/O area

An application program must identify a checkpoint I/O area for the checkpoint ID that it passes to AR/CTL as a parameter of the CHKP call. The application program also can use this area for a checkpoint ID to use with the XRST call. To be compatible with IMS, the length must be set to 12 bytes.

The application program must initialize the checkpoint I/O area to blanks before issuing the restart call.

Define the checkpoint I/O area as a level 01 entry in working storage. You can further define the area with level 02 entries. The following example shows a typical checkpoint I/O area in COBOL:

IDENTIFICATION DIVISION.
...
DATA DIVISION.
WORKING-STORAGE SECTION.
01   CHKPAREA.
     02 CHKPID PICTURE X(8).
     02 FILLER PICTURE X(4).

Coding the checkpoint I/O area

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