COBOL Manual for TNS and TNS/R Programs

Procedure Division Verbs
HP COBOL Manual for TNS and TNS/R Programs—522555-006
9-255
STARTBACKUP
°
TNS/R
The fault-tolerant facility checkpoints the global-data portion of the globals-
heap segment, the main stack, and all open files when the STARTBACKUP
statement is executed; however, your program must contain a CHECKPOINT
statement to verify the creation of a backup process and to establish a valid
takeover point in the program code (rather than in the run-time library).
•
Whether to Back Up the Extended-Storage Section (COBOL85 Compiler Only)
If the value of backup-ext is 0, the STARTBACKUP statement does not back up
the Extended-Storage Section. If a backup process takes over, the contents of any
data item in the Extended-Storage Section is undefined unless that data item is
explicitly referenced in a CHECKPOINT statement. If the contents are undefined,
VALUE clauses have no effect and the extended stack functions incorrectly. (The
extended stack is important only if the HP COBOL program calls a non-COBOL
routine that uses it. FORTRAN routines, for example, can use the extended stack.)
If the value of backup-ext is 1, the STARTBACKUP statement backs up the
Extended-Storage Section. If a backup process takes over, the contents of any
data item in the Extended Storage Section are determined:
If the data item … Then its contents are …
has a VALUE clause as specified by the VALUE clause
has no VALUE clause and the BLANK directive
applies
spaces
and the NOBLANK
directive applies
undefined