“Automatic restart” is a system function which supports unmanned operation. It enables automatic reloading of the operating system after a system crash. If necessary, a system memory dump can be taken by means of SLED or SNAP without operator intervention.
Automatic restart can be activated or deactivated by the operator (see the commands SET-RESTART-OPTIONS MODE=*ON/*OFF, DUMP=*SLED/*SNAP and SHOW-RESTART-OPTIONS). By default, the function is set to off.
Preconditions for automatic restart with SLED
The preconditions for a FAST startup must have been met and no incorrect REPs or parameters may be present.
If SLED is used to take a system dump, one of the following two files must be available
$TSOS.SLEDFILE (for SLED without parameter file)
$TSOS.SYSPAR.SLED.<ver> (for SLED with parameter file)
If, in the case of SLED without a parameter file, the $TSOS.SLEDFILE already contains a dump (i.e. it is not logically empty), a new dump cannot be taken and the system is immediately reloaded in accordance with the specifications in the SET-RESTART-OPTIONS command.
The dump file $TSOS.SLEDFILE can also be a “large” file (more than 32 GB) and be located on the home pubset.
Preconditions for automatic restart with SNAP
The SNAP function must be enabled. This is done using the SNAP-ACTIVE-SWITCH parameter (SNAP parameter record) in the startup parameter service (see "Snapshot initialization (SNAP)") or, when the system is running, using the ACTIVATE-SNAPSHOT command.
If the system file $TSOS.SNAPFILE does not exist, it is created at startup (SNAP-ACTIVE-SWITCH=ON parameter) in the standard size or in the specified size when the ACTIVATE-SNAPSHOT command is executed.
Information on the status of SNAP is provided by the SHOW-SNAPSHOT-STATUS command.