SNAP saves BS2000-specific diagnostic information under the control of the independent non-BS2000-specific SNAP-EXEC (see the description of the SNAP function in the “Diagnostics Handbook” [14]). When this is done, BS2000 and its applications are put on hold for a maximum of 24 seconds (see the system parameter SNAPTIME).
The SNAP function is automatically activated when BS2000 starts up if the SNAP-ACTIVE-SWITCH parameter of the SNAP parameter record is not set to “OFF”.
The keyword for the snapshot parameter record is SNAP.
There is just one parameter for SNAP.
If an invalid value is specified in the parameter record, SNAP is implicitly deactivated (OFF) and an error message is output during startup of BS2000. If there is no SNAP-ACTIVE-SWITCH parameter, the default (ON) comes into effect.
Format of the parameter record for snapshot initialization
| SNAP-ACTIVE-SWITCH = ON / ON'BLANK' *) / OFF |
*) 'BLANK' = 1 blank
SNAP-ACTIVE-SWITCH = ON / ON'BLANK'
Default: the SNAP function is to be activated for the current session.
If the system file $TSOS.SNAPFILE does not exist, it is automatically created at startup (in the standard size).
If the SNAPFILE still contains a SNAP dump from the previous session (Previous SNAP), this SNAP dump is copied in the the new session, i.e. it is provided with an index structure and written to a new file under the SYSSNAP user id.
SNAP-ACTIVE-SWITCH = OFF
SNAP is not initialized at system initialization time. It is initially not available for this session. SNAP calls are terminated with an appropriate return code. SNAP can be activated dynamically later using the ACTIVATE-SNAPSHOT command. Any Previous SNAP remains unchanged in the new session.
The parameter values ON and OFF can also be specified in inverted commas ('ON' / 'ON ' / 'OFF').
Extract from the parameter file
/BS2000 PARAMS : /BEGIN SNAP SNAP-ACTIVE-SWITCH=ON /EOF : /END-PARAMS