How does the operating system manage multiple active processes?

The operating system manages multiple active processes primarily through a technique called time-sharing. In a time-sharing environment, the CPU's time is divided among active processes, allowing them to run concurrently while giving the impression that they are executing simultaneously. This is accomplished by rapidly switching the CPU's focus from one process to another, enabling each process to get a small time slice of CPU time.

This approach maximizes CPU usage and system responsiveness, as it allows users to interact with their applications without significant delay. The operating system is responsible for scheduling, which determines the order and duration each process gets to execute, thereby ensuring fair allocation of resources to all active processes.

In contrast, running processes on separate servers does not directly address the management of active processes on a single system. Allowing user control over all processes could lead to system instability or security vulnerabilities, as users may not always make optimal choices about which processes should run. Limiting user access to background processes does not effectively manage active processes and might restrict necessary functionalities required for full system operation.