Coding the checkpoint I/O area
CHKPcall. The application program also can use this area for a checkpoint ID to use with the
XRSTcall. 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).