What is process preemption and why is it necessary?

Process preemption refers to the act of temporarily suspending the execution of a running process in order to allocate the CPU to another process. This is necessary in order to ensure fairness, efficiency, and responsiveness in the operating system.

There are several reasons why process preemption is necessary:

1. Fairness: Preemption ensures that all processes have a fair chance to execute on the CPU. Without preemption, a long-running process could monopolize the CPU, causing other processes to wait indefinitely. By preempting processes, the operating system can allocate CPU time fairly among all processes, preventing any single process from dominating the system resources.

2. Efficiency: Preemption allows the operating system to make better use of the available CPU resources. By interrupting a running process and allocating the CPU to another process, the operating system can maximize the utilization of the CPU. This leads to improved overall system performance and throughput.

3. Responsiveness: Preemption enables the operating system to quickly respond to high-priority tasks or events. In a multitasking environment, there may be processes with different priorities or time-critical tasks that require immediate attention. By preempting lower-priority processes, the operating system can ensure that high-priority tasks are executed promptly, enhancing system responsiveness.

4. Resource allocation: Preemption facilitates the efficient allocation of system resources. In some cases, a process may be waiting for a particular resource, such as I/O or memory. By preempting the process, the operating system can allocate the required resource to another process that can make progress, preventing resource wastage and improving resource utilization.

Overall, process preemption plays a crucial role in maintaining fairness, efficiency, and responsiveness in the operating system. It allows for better resource allocation, prevents process monopolization, and ensures that high-priority tasks are executed promptly.