COBOL Manual for TNS and TNS/R Programs

Procedure Division Verbs
HP COBOL Manual for TNS and TNS/R Programs—522555-006
9-253
STARTBACKUP
backup-ext
is ignored by the NMCOBOL compiler. For a program compiled by the COBOL85
compiler, backup-ext works only if the program runs in the Guardian
environment and in the CRE. It is an integer numeric literal or an integer numeric
data item. Its legal values and their meanings are:
Usage Considerations:
•
When STARTBACKUP Statement Has No Effect
In the OSS environment, or in the Guardian environment when PARAM NONSTOP
OFF is active, the STARTBACKUP statement has no effect.
•
NONSTOP Compiler Directive
The STARTBACKUP statement can appear in a source program only when the
compiler finds the NONSTOP directive before it finds an Identification Division
header (see NLD).
•
Backup Process and Takeover Points
When the process is qualified to execute as a process pair, successful execution of
the STARTBACKUP statement establishes and initializes a backup process. The
STARTBACKUP statement does not itself establish a valid takeover point; this is a
function of the CHECKPOINT, OPEN, or CLOSE statement.
Code a CHECKPOINT statement after each STARTBACKUP statement so that the
new backup process will have all the data it needs for a possible takeover.
3 The primary process, rather than the fault-tolerant facility, reads the $RECEIVE
file and takes appropriate action for system messages. In addition, if the
primary process encounters a trap condition, it enters the DEBUG procedure.
When this option is in force and the backup process fails, the primary process
must re-execute the STARTBACKUP statement to reestablish the backup.
(This is considered an advanced option because it requires direct calls to the
operating system. If you use this option, see the information on interprocess
communication and checkpointing in the Guardian Programmer’s Guide.)
Value Meaning
0 (default) The Extended-Storage Section is not to be backed up.
1 The Extended-Storage Section is to be backed up.
Note. If the primary process executes a STOP RUN statement, the backup process also
stops, regardless of the specified option.
Value Meaning (page 2 of 2)