Cooperative Multitasking:
1. Task Yielding: In cooperative multitasking, tasks voluntarily give up control of the processor to other tasks. This is achieved through a "yield" statement or equivalent mechanism in the programming language.
2. Reliance on Task Cooperation: Each task is responsible for explicitly relinquishing control of the CPU to allow other tasks to execute. If a task fails to yield control, the entire system may hang or become unresponsive.
3. No Priority-Based Scheduling: Since tasks cooperate and decide when to yield, there's no concept of priority-based scheduling. All tasks have equal priority, and the order of execution solely relies on the yielding behavior of each task.
4. Simplicity: Cooperative multitasking is relatively simple to implement compared to preemptive multitasking. It doesn't require a scheduling mechanism or sophisticated algorithms to manage tasks.
5. Common in Early Operating Systems: Cooperative multitasking was commonly used in early operating systems where simplicity was prioritized over performance or handling complex workloads.
Preemptive Multitasking:
1. OS Control Over Task Scheduling: In preemptive multitasking, the operating system (OS) has control over task scheduling and decides when to switch tasks. The OS preempts tasks that have been running for a predetermined time slice and gives other tasks a chance to execute.
2. Priority-Based Scheduling: Preemptive multitasking allows for priority-based scheduling, meaning that higher-priority tasks are given precedence over lower-priority tasks. This ensures better resource allocation and responsiveness to time-critical tasks.
3. Forced Context Switching: The OS can forcibly suspend a task's execution and save its state to memory. When the task resumes, its previous state is restored, ensuring continuity and integrity.
4. Improved Performance: Preemptive multitasking provides more efficient and predictable task scheduling, leading to better overall system performance and responsiveness.
5. Complexity: Preemptive multitasking involves more complex algorithms and mechanisms for scheduling, context switching, and managing task states, making its implementation more challenging.
In summary, cooperative multitasking relies on voluntary task yielding, with tasks having equal priority and no OS control over scheduling. It is simpler to implement but can lead to system hangs if tasks fail to cooperate. Preemptive multitasking, on the other hand, provides greater OS control, allows priority-based scheduling, and ensures predictable task execution. It is more efficient and suitable for modern computing environments that demand high performance and responsiveness.