GDSX (Extended General Device Support) Manual

User Exit Descriptions
Extended General Device Support (GDSX) Manual—529931-001
9-10
USER^BACKUP
END;
END;
INT Z^EXT^SU^SIZE; ! NOT USER MODIFIABLE
INT Z^ASSOC;
INT Z^AUTOSTOP;
INT Z^NOWAIT^DEPTH;
INT Z^SUTYPE;
INT Z^USER^DATA[0:127];
END;
USER^BACKUP
USER^BACKUP allows you to checkpoint global data that is required for successful
takeover in the event of failure.
If GDSX is run as a process pair, at startup time the primary GDSX process
checkpoints the following to the backup process:
•
Config^params^template of configuration parameters
•
File control blocks
•
Task control blocks
•
Receive control blocks
•
Line control blocks
•
Device control blocks
•
Process control blocks
•
Logical device control blocks
See Fault Tolerance on page 2-28 for more information on the fault-tolerance
processing at startup time.
After this data is checkpointed, TSCODE’s backup task (task 3) in the primary GDSX
process calls USER^BACKUP, giving you the opportunity to checkpoint your own
global data declared in a named or private global data block.
If at some later time the primary process dies, in the new primary, which was formerly
the backup process, calls USER^TAKEOVER, followed by USER^BACKUP.
The USER^BACKUP procedure is only called once in the life of a GDSX primary
process.
Considerations
•
The TSCODE-supported FAULT procedure should only be called from the
USER^BACKUP exit with its noretn parameter equal to 0. See the description of
the FAULT on page 8-22.
PROC USER^BACKUP