This is the model in which the database originally works, whereby a Server Process is created for each User Process that requests to connect to the database.

You can monitor the number of Server Processes working in the database through the operating system. In the Windows operating system, you can follow this through the Task Manager.

In reality, they are not Operating System Processes, but rather appear as Single Oracle.exe Process. But you can know the number of Processes through the Thread count in the Task Manager.

Of course, you can end all server processes via End Process.