The main difference between preemptive and nonpreemptive kernel is that the preemptive kernel allows a process in execution in the kernel mode to be interrupted by some other process, while a nonpreemptive kernel does not allow a process in execution in the kernel mode to be interrupted by some other process.
An operating system works as the interface between the hardware resources and the user programs. It handles multiple important tasks of an operating system. Some of them include process scheduling, protecting the data, memory management and file handling. Furthermore, the kernel is the core of an operating system. There are two types of kernels; the preemptive and the nonpreemptive kernel.
Key Areas Covered
1. What is Preemptive Kernel
– Definition, Functionality
2. What is Nonpreemtive Kernel
– Definition, Functionality
3. Difference Between Preemptive and Nonpreemtive Kernel
– Comparison of Key Differences
Kernel, Nonpreemptive Kernel, Operating System, Preemptive Kernel
What is Preemptive Kernel
A computer system operates in two modes: kernel mode and user mode. Kernel mode is a more privileged mode than the user mode. In kernel mode, the programs can directly access the memory and hardware resources while in user mode, the program cannot directly access memory and hardware resources.
Preemptive Kernel is a kernel that allows interrupting a program in the middle of the executing. In other words, the kernel is capable of stopping the execution of the currently running process and allowing some other process to execute. As preemptive kernel does not allow the processor to run a process for a long time continuously, this type of kernel is more secure.
What is Nonpreemptive Kernel
The nonpreemptive kernel does not allow interrupting the currently running process. It does not allow stopping the execution of the running process. The process will be executed until it exits the kernel mode or is blocked. Moreover, in the nonpreemptive kernel, there is only a single process active in the kernel at a time. Therefore, this type of kernel does not cause race condition on the kernel data structures. As a process runs for a long period of time, nonpreemptive kernels are not responsive like preemptive kernels.
Difference Between Preemptive and Nonpreemptive Kernel
The preemptive kernel is a type of kernel that allows a process to be removed or replaced while it is running in the kernel mode. In contrast, the nonpreemptive kernel is a type of kernel that allows a process running in kernel mode to be preempted. Thus, this is the main difference between preemptive and nonpreemptive kernel.
It is difficult to design preemptive kernels, whereas it is easier to design nonpreemptive kernels. Hence, this is an important difference between preemptive and nonpreemptive kernel.
Moreover, the preemptive kernel is more suitable for real-time programming than the nonpremptive kernel.
Security is another difference between preemptive and nonpreemptive Kernel. The preemptive kernel is more secure while the nonpreemtive kernel is risky.
Furthermore, commercial versions such as Solaris, IRIX and Linux (from 2.6 kernel) are examples for the preemptive kernel. On the other hand, Windows XP and 2000 are examples for nonpreemptive kernels.
In brief, the main difference between preemptive and nonpreemptive kernel is that the preemptive kernel allows a process in execution in the kernel mode to be interrupted by some other process while a nonpreemptive kernel does not allow that to happen. Also, nonpreemptive kernels are easier to design. However, preemptive kernels are more secure and more useful in real-world scenarios.
1.“Preemptive and Nonpreemptive Kernels.” Preemptive and Nonpreemptive Kernels via Commons Wikimedia
1.”operating system between user and computer” By mlibre – Own work (CC0) via Commons Wikimedia