Opening the ACB during recovery from an application failure

During the recovery process, the application program issues the OPEN ACB, using the original ACBNAME, to reconnect to VTAM®. Upon return of the OPEN ACB macroinstruction, VTAM will indicate that this application is a persistent instance (the opening application program has taken over or recovered an ACB that was previously used by an application program that was enabled for persistence).

During the OPEN processing, VTAM verifies that the following conditions are true.

Original application had enabled persistence
Recovering application is capable of persistence
Recovering application's MACRF value matches the original application's MACRF value.
Recovering application's support for network-qualified names matches that of the original application.

If any of the preceding requirements are not met, the OPEN ACB fails. The state of the application and sessions remains unaltered. If all requirements are met, VTAM begins the recovery process.

The recovering application does not need to re-establish persistence (SETLOGON OPTCD=PERSIST). When the application program opens an ACB for which persistence had been previously enabled, persistence remains enabled.

During the application recovery process, VTAM ensures that the allocated resources will be available during session recovery. VTAM then cancels the persistent session timer and completes the OPEN processing. After processing the OPEN ACB, VTAM changes the application's state from inhibited to the appropriate state as shown in Table 1.