Difference between Preemptive and Cooperative Multitasking

Multitasking is the method of running several programs or processes at the same time. Most modern OS support multitasking for maximum processor utilization. There are mainly two types of multitasking which are Preemptive and Cooperative multitasking.

In this article, you will learn about the difference between Preemptive and Cooperative multitasking in the operating system. But before discussing the differences, you must know about Preemptive and Cooperative multitasking in the operating system.

What is Preemptive Multitasking?

The operating system may start a context switching from one process that is currently running to another during preemptive multitasking. In other words, the OS enables you to stop the execution of the existing process and reallocate the processor to another. The operating system (OS) utilizes a set of criteria to determine how long a process should run before granting access to the OS to another process.

Some OSs assigns priorities to the processes. In those circumstances, the process with the higher priority is executed first before the process with the lower priority. After that, the higher priority processes get controlled as they are initiated. Furthermore, those processes may be given extended time slices to complete.

Example: It is utilized by UNIX, Windows 95, and Windows NT.

What is Cooperative Multitasking?

Cooperative multitasking is also referred to as preemptive multitasking. The operating system never starts context switching from one executing process to another during cooperative multitasking. A context switch occurs when processes voluntarily yield control regularly or when they are inactive or logically halted to enable many apps to run concurrently. Additionally, all processes cooperate in cooperative multitasking for the scheduling method to work.

In cooperative multitasking, the OS process scheduler is referred to as the cooperative scheduler. Applications may be implemented more quickly, but it is rarely utilized in large and complex systems. Although, programming languages like Python and JavaScript are utilized with a single-threaded event loop on their execution.

Example: It is utilized by Mac OS version 8.0-9.2.2 and Windows 3.x.

Key differences between Preemptive and Cooperative Multitasking in Operating System

Here, you will learn about the various key differences between Preemptive and Cooperative multitasking in operating systems. Some main differences between Preemptive and Cooperative multitasking in operating systems are as follows:

1. The OS may begin context switching from one running process to another during preemptive multitasking. On the other hand, the OS never initiates context switching from one process to another when using cooperative multitasking.
2. Preemptive multitasking interrupts programs and grants control to processes that are not under the control of the application. On the other hand, cooperative multitasking never unexpectedly interrupts a process.
3. Preemptive multitasking occurs when a malicious application initiates an indefinite loop that only affects itself and has no effect on other programs or threads. On the other hand, a malicious application may block the entire system in cooperative multitasking by busy waiting or performing an indefinite loop and refusing to give up control.
4. Preemptive multitasking forces apps to share the processor, whether they want to or not. On the other hand, in cooperative multitasking, all applications must collaborate for it to work. If one program doesn't cooperate, it may use all of the processor resources.
5. UNIX, Windows 95, and Windows NT OS use preemptive multitasking. On the other hand, Macintosh OS versions 8.0-9.2.2 and Windows 3.x use cooperative multitasking.

Head-to-head comparison between the Preemptive and Cooperative Multitasking in Operating System

The operating system has various head-to-head comparisons between Preemptive and Cooperative Multitasking in the operating systems. Some comparisons of Preemptive and Cooperative Multitasking in operating systems are as follows:

Conclusion

In summary, both preemptive and cooperative multitasking are two types of multitasking. The primary distinction between these OS is that the OS may initiate a context switch from a running process to another in preemptive multitasking. In contrast, the OS doesn't start a context switch from an existing process to another in cooperative multitasking.