The files listed above must be installed in the system prior to starting the DAB subsystem for the first time.
DAB is loaded automatically at BS2000 startup (setting in the supplied standard subsystem catalog entry).
The command /STOP-SUBSYSTEM SUBSYSTEM-NAME=DAB[,VERSION=21.0] can be used to unload DAB during the session (i.e. without BS2000 shutdown) under the following conditions:
No (more) cache areas exist.
No SM2 measurements are being made for DAB (active measuring can be stopped by means of the SM2 statement
//STOP-MEASUREMENT-PROGRAM TYPE=*DAB).All asynchronous I/O jobs started during cache operation for a cache area released by means of
/STOP-DAB-CACHINGhave terminated.
DAB can subsequently be (re)started using the command /START-SUBSYSTEM SUBSYSTEM-NAME=DAB[,VERSION=21.0].
If the BS2000 system is terminated despite the fact that it still has cache areas configured (shutdown), the data of these cache areas is written back by DAB within the framework of the shutdown and (except for requests by subsystem parameters) then the cache area is released. It is, however, advisable to release any existing cache areas by means of the appropriate DAB commands prior to system shutdown so that it is possible to react to errors, if required.
Subsystem shutdown should be checked with the /SHOW-SUBSYSTEM-STATUS command (status NOT CREATED). Messages which reject unloading the subsystem are only output to the console or logged in the CONSLOG file.