Entire DB2 process model is controlled by Base System Utilities.
The processes or threads are responsible for Initialization and Controlling of all processes.
db2start:Its a cmd to start the instance,checks for db2nodes.cfg if its present or not.Later it forks/exec db2star2 and waits for its completion.
db2star2: Its the actual start process. Does authorization/licenses. Later it forks/exec db2sysc (system controller) and waits for its completion.
db2sysc connects to instance shared memory rename itself as watchdog and later it starts generic daemon spawner to handle complete process model.
Hope this is enough :-)
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